TWM619738U - Relay logic for double-bus power system with tie circuit breaker and double-bus power system - Google Patents

Abstract

The present invention discloses a relay logic and a double-bus power system. Wherein, a signal 87Z1 output by the SEL-487B relay controls the tie circuit breaker and the first circuit breaker of the double-bus power system, and a signal 87Z2 output by the SEL-487B relay controls the tie circuit breaker and the second circuit breaker of the double-bus power system. The relay logic of the SEL-487B relay includes a first AND gate and a second AND gate. The first AND gate has three first input terminals and a first output terminal. One of the first input terminals is connected to a signal PLT12, the other of the first input terminals is connected to a signal PCT06Q, and another one of the input terminals is connected to a reverse signal 87ST3. The second AND gate has two second input terminals and a second output terminal. One of the second input terminals is connected to the first output terminal, and the other of the second input terminals is connected to a signal 87R1 or a signal 87R2, and the second output terminal outputs the signal 87Z1 or the signal 87Z2.

Description

Protection relay logic of dual-bus-bar power system with connecting circuit breaker, and dual-bus-bar power system

The present invention relates to a protection relay logic, in particular to a protection relay logic of a dual busbar power system with a connected circuit breaker, and a dual busbar power system applying the protection relay logic.

The bus (Bus) of the power (power supply) system is one of the important components of power plants and substations. Due to the large number of power and switchgear connected to the bus, it has the status of a power transmission hub and is the collection and distribution of electrical energy. Important equipment. Compared with transmission lines and other equipment, although the probability of bus failure is low, the impact of bus failure is quite large. Therefore, it is very important to install bus protection relays that can quickly isolate faults. Bus protection The refusal or malfunction of the electrical station will cause serious harm to the power system.

The digital bus protection relay is a split-phase low-impedance bus differential protection that uses the principle of variable ratio suppression. It has a current comparator saturation detection lockout logic function and a current phase (direction) judgment logic function, which can avoid external The large fault current causes the difference current generated after the current comparator is saturated, which causes the busbar relay to trip, which strengthens the safety of the busbar protection. In other words, in addition to striving for the fast action of the busbar protection relay to provide reliable protection in the event of an internal failure, it also needs to focus on considering the occurrence of an external failure, not due to CT Failure or the current comparator. Saturation causes insufficient protection safety of the bus protection relay action. Therefore, how to both reduce equipment damage and provide continuous and stable power supply depends on whether the performance and logical planning of the bus station are appropriate.

Take the bus protection relays of the 161kV power system of Taiwan Electric Power Company as an example. The SEL-487B type electrical relays manufactured by SEL in the United States account for nearly half of the number, but due to different versions, their logical planning is also different. Under the same hypothetical situation, the action situation of the electric relay will be inconsistent. In addition, in some versions, if an external fault occurs under the abnormality of the comparator circuit, the relay will trip; in some versions, the protection function will be blocked during a bus power failure or a single bus operation.

The purpose of this new model is to provide a protection relay logic for a dual-bus power system with a connected circuit breaker, and a dual-bus power system applying the protection relay logic, which can improve the protection logic of the existing version of the SEL-487B relay Blind spots, so that the dual-bus power system with connecting circuit breakers can provide stable power supply.

In order to achieve the above objective, according to the protection relay logic of a dual-bus-bar power system with connected circuit breakers of the present invention, the dual-bus-bar power system includes a first bus bar, a second bus bar, a connected circuit breaker, and a second bus bar. A power device, a second power device, and a SEL-487B electrical relay. The circuit breaker is connected between the first bus bar and the second bus bar. The first power device is connected to the first through a corresponding first circuit breaker. The bus bar, the second power device is connected to the second bus bar through a corresponding second circuit breaker, the SEL-487B electrical relay is electrically connected to the circuit breaker, the first circuit breaker and the second circuit breaker, and the SEL-487B electrical relay output A signal 87Z1 controls the contact breaker and the first circuit breaker, and a signal 87Z2 output by the SEL-487B electrical relay controls the contact breaker and the second circuit breaker; the SEL-487B electrical relay has the protection relay logic, the protection relay The logic includes a first and gate and a second and gate. The first and gate has three first input terminals and a first output terminal. One of the first input terminals is connected to a signal PLT12, and the other of the first input terminals is connected to a signal PCT06Q. One of the input terminals is connected to a reverse signal 87ST3. The second and gate has two second input terminals and a second output terminal, one of the second input terminals is connected to the first output terminal, and the other of the second input terminals is connected to a signal 87R1 or a signal 87R2, And the second output terminal outputs the signal 87Z1 or the signal 87Z2; among them, when applied to a first zone (Zone 1), the other of the second input terminals is connected to the signal 87R1, and the second output terminal outputs the signal 87Z1; When applied to a second zone (Zone 2), the other one of the second input terminals is connected to the signal 87R2, and the second output terminal outputs the signal 87Z2.

In an embodiment, the first power device or the second power device is a power source or a load.

In one embodiment, the protection relay logic further includes a judging element, a first comparator, and a second comparator. When applied to the first zone (Zone 1), one of the input terminals of the determining element is connected to a signal IRT1, and the other of the input terminals of the determining element is connected to a signal IOP1; when applied to the second zone (Zone 2), One of the input ends of the judgment element is connected to a signal IRT2, and the other of the input ends of the judgment element is connected to a signal IOP2. When applied to the first zone (Zone 1), one of the input terminals of the first comparator is connected to a signal IOP1, and the other of the input terminals of the first comparator is connected to a signal O87P; when applied to the second zone (Zone 2) When one of the input terminals of the first comparator is connected to a signal IOP2, the other one of the input terminals of the first comparator is connected to a signal O87P. When applied to the first zone (Zone 1), one of the input terminals of the second comparator is connected to a signal IOP1, and the other of the input terminals of the second comparator is connected to a signal S87P; when applied to the second zone (Zone 2) When one of the input terminals of the second comparator is connected to a signal IOP2, the other one of the input terminals of the second comparator is connected to a signal S87P.

In one embodiment, the protection relay logic further includes a delay action element and a selection element. The input terminal of the delay action element is connected to the output terminal of the second comparator. One of the input terminals of the selection element is connected to the output terminal of the delay action element, and the other of the input terminals is connected to a ground terminal.

In one embodiment, the protection relay logic further includes a third sum gate. The third sum gate has four third input terminals and a third output terminal. One of the third input terminals is connected to the judgment element The other of the third input terminals is connected to the output terminal of the first comparator, and the other of the third input terminals is connected to a signal FAULT1 or a signal FAULT2. One of the third input terminals and the output terminal of the third and gate output signal 87R1 or 87R2; among them, when applied to the first zone (Zone 1), one of the third input terminals is connected to the signal FAULT1, the output terminal of the third and gate outputs the signal 87R1; when applied to the second zone (Zone 2), one of the third input terminals is connected to the signal FAULT2, and the output terminal of the third and gate outputs the signal 87R2.

In order to achieve the above objective, according to the protection relay logic of a dual-bus-bar power system with connected circuit breakers of the present invention, the dual-bus-bar power system includes a first bus bar, a second bus bar, a connected circuit breaker, and a second bus bar. A power device, a second power device, and a SEL-487B electrical relay. The circuit breaker is connected between the first bus bar and the second bus bar. The first power device is connected to the first through a corresponding first circuit breaker. The second power device is connected to the second bus bar through a corresponding second circuit breaker. A signal 87Z1 output by the SEL-487B electrical relay controls the connection circuit breaker and the first circuit breaker, and a signal output by the SEL-487B electrical relay Signal 87Z2 controls the connection circuit breaker and the second circuit breaker; the SEL-487B electrical relay has the protection relay logic. The protection relay logic includes a first and gate, a second and gate, a third and a gate, and a selection element . The first and gate has three first input terminals and a first output terminal. One of the first input terminals is connected to a signal PLT12, and the other of the first input terminals is connected to a reverse signal 87STCZ1. One of the first input terminals is connected to a signal 87CZ1. The second and gate has two second input terminals and a second output terminal, one of the second input terminals is connected to the first output terminal, and the other of the second input terminals is connected to a signal 87R1 or a signal 87R2, The second output terminal outputs the signal 87Z1 or 87Z2. When applied to a first zone (Zone 1), the other of the second input terminals is connected to the signal 87R1, and the second output terminal outputs the signal 87Z1; In a second zone (Zone 2), the other one of the second input terminals is connected to the signal 87R2, and the second output terminal outputs the signal 87Z2. The third and gate has four third input terminals and a third output terminal, one of the third input terminals is connected to a signal FDIF1 or signal FDIF2, and the other of the third input terminals is connected to a signal 87O1 or signal 87O2, one of the third input terminals is connected to a signal FAULT1 or a signal FAULT2, and the output terminal of the third gate outputs a signal 87R1 or a signal 87R2. When applied to the first zone (Zone 1), the One of the third input terminals is connected to the signal FDIF1, the other of the third input terminals is connected to the signal 87O1, another of the third input terminals is connected to the signal FAULT1, and the output terminal of the third and gate outputs the signal 87R1; In the second zone (Zone 2), one of the third input terminals is connected to the signal FDIF2, the other of the third input terminals is connected to the signal 87O2, and the other of the third input terminals is connected to the signal FAULT2, The output terminal of the third and gate outputs signal 87R2. The output signal of the output terminal of the selection element is reversely input to one of the third input terminals.

In one embodiment, the protection relay logic further includes a judging element, a first comparator, and a second comparator. When applied to the first zone (Zone 1), one of the input ends of the judging element is connected to a signal IRT1, the other of the input ends of the judging element is connected to a signal IOP1, and the output end of the judging element outputs a signal FDIF1; In the second zone (Zone 2), one of the input ends of the judgment element is connected to a signal IRT2, the other of the input ends of the judgment element is connected to a signal IOP2, and the output end of the judgment element outputs a signal FDIF2. When applied to the first zone (Zone 1), one of the input terminals of the first comparator is connected to the signal IOP1, the other of the input terminals of the first comparator is connected to a signal O87P, and the output terminal of the first comparator outputs a signal 87O1; when applied to the second zone (Zone 2), one of the input terminals of the first comparator is connected to the signal IOP2, the other of the input terminals of the first comparator is connected to the signal O87P, and the output terminal of the first comparator is output Signal 87O2. When applied to the first zone (Zone 1), one of the input terminals of the second comparator is connected to the signal IOP1, and the other of the input terminals of the second comparator is connected to a signal S87P; when applied to the second zone (Zone 2 ), one of the input terminals of the second comparator is connected to the signal IOP2, and the other of the input terminals of the second comparator is connected to the signal S87P.

In one embodiment, the protection relay logic further includes a delay action element, the input terminal of which is connected to the output terminal of the second comparator; wherein one of the input terminals of the selection element is connected to the output terminal of the delay action element, and its input The other of the terminals is connected to a ground terminal.

In one embodiment, the output terminal of the selection element is directly connected to the ground terminal.

To achieve the above purpose, a dual-bus power system according to the present invention includes a first bus bar and a second bus bar, a connecting circuit breaker, a first power device, a second power device, and a SEL-487B Electric station. The connecting circuit breaker is connected between the first bus bar and the second bus bar. The first power device is connected to the first bus bar through a corresponding first circuit breaker. The second power device is connected to the second bus bar through a corresponding second circuit breaker. The SEL-487B electrical relay is electrically connected to the circuit breaker, the first circuit breaker and the second circuit breaker, a signal 87Z1 output by the SEL-487B electrical relay controls the contact circuit breaker and the first circuit breaker, and one of the SEL-487B electrical relay outputs Signal 87Z2 controls the connection circuit breaker and the second circuit breaker. Among them, the SEL-487B relay has the protection relay logic of the above-mentioned embodiment.

As mentioned above, in the protection relay logic of the dual-bus power system with connected circuit breakers and the dual-bus power system applying the protection relay logic of the present invention, the existing version can be improved by the above-mentioned logic planning The blind spot of the protection logic of the SEL-487B electrical relay also makes the protection logic of the existing version of the SEL-487B electrical relay consistent, which in turn enables the dual-bus power system with connected circuit breakers to provide stable power supply.

The following will describe the protection relay logic of the dual-bus-bar power system with connected circuit breakers according to the embodiment of the present invention with reference to related drawings, and the dual-bus-bar power system. The same components will be described with the same reference symbols. .

This new type of protection relay logic for a dual-bus power system with a connected circuit breaker is applied to the bus current differential protection relay made by the American SEL company (hereinafter referred to as SEL-487B relay or 87B). Power technicians who are familiar with the SEL-487B electrical relay can learn from the technical manuals, materials, or other related power technical materials provided by the company, the physical meaning of the signals, codes or symbols appearing in the text or diagrams . In addition, some terms, symbols, signals or codes appearing in this text or in the drawings should be understood by those skilled in the field of electric power technology.

FIG. 1A is a schematic diagram of the architecture of a dual-bus-bar power system with a connected circuit breaker according to an embodiment of the new type, and FIG. 1B is a schematic diagram of the functional block diagram of the SEL-487B electrical relay. Here, 87Z1 and 87Z2 shown in FIG. 1A do not indicate that the device or line outputs signals 87Z1 and 87Z2, but that the signals output by the device or line are related to the signals of 87Z1 and 87Z2 (for example, correspond to each other). In addition, FIG. 1B only shows one SEL-487B electrical relay, and those skilled in power systems should know that a three-phase system can have three SEL-487B electrical relays to protect the corresponding three-phase electrical equipment.

Please refer to Figures 1A and 1B, the dual-bus power system 1 includes a first bus #1 BUS, a second bus #2 BUS, a connection circuit breaker CB0, a first power device, and a second bus. Power equipment and a SEL-487B electric station (Figure 1B).

The connecting circuit breaker CB0 is connected between the first bus #1 BUS and the second bus #2 BUS. The first power device can be connected to the first bus #1 BUS through a corresponding first circuit breaker, and the second power device can be connected to the second bus #2 BUS through a corresponding second circuit breaker. Among them, the first power device or the second power device may be a power source or a load (the load may be a power distribution line or other power supply system or power supply network). In some embodiments, the dual busbar power system may have multiple first power devices (corresponding to multiple first circuit breakers) and multiple second power devices (corresponding to multiple second circuit breakers).

As shown in FIG. 1A, in this embodiment, there are two first power devices S1, L1 corresponding to two first circuit breakers CB1, CB3, and two second power devices S2, L2 corresponding to two second circuit breakers CB2. , CB4 as an example. Among them, the first power device S1 is, for example, a generator, which is connected to the first bus #1 BUS through the first circuit breaker CB1; the first power device L1 is, for example, a load, which is connected to the first bus through the first circuit breaker CB3 Row #1 BUS; the second power device S2 is, for example, a generator, which is connected to the second bus #2 BUS through a second circuit breaker CB2, and the second power device L2 is, for example, a load, which is connected to The second bus #2 BUS. However, it is not limited to this. In different embodiments, the first power device or the second power device may be other power distribution lines or power distribution networks, and the number may be greater than or equal to three, depending on the actual power supply network. Certainly.

The dual busbar power system 1 of this embodiment may further include four isolation switches DS1 to DS4, and the isolation switches DS1 to DS4 may be manual or automatic isolation switches (ie, automatic circuit breakers). Here, the isolation switches DS1 to DS4 are based on automatic circuit breakers as an example. The isolating switch DS1 is correspondingly connected between the first circuit breaker CB1 and the second bus #2 BUS, the isolating switch DS2 is correspondingly connected between the second circuit breaker CB2 and the first bus #1 BUS; the isolating switch DS3 is correspondingly connected to Between the first circuit breaker CB3 and the second bus #2 BUS, the isolating switch DS4 is correspondingly connected between the second circuit breaker CB4 and the first bus #1 BUS.

In addition, the dual-bus-bar power system 1 of this embodiment may also include six current concentrators CT0, CT0', CT1 to CT4. The current comparator CT0 can sense the current passing through one side of the circuit breaker CB0 (between the circuit breaker CB0 and the first bus #1 BUS), and output the sensing signal SS to the SEL-487B relay (Figure 1B) The current comparator CT0' can sense the current passing through the other side of the circuit breaker CB0 (between the circuit breaker CB0 and the second bus #2 BUS), and output the sensing signal SS to the SEL-487B relay; The current transformers CT1～CT4 can respectively sense the current passing through the first circuit breaker CB1, CB3 and the second circuit breaker CB2, CB4 (CT1 corresponds to CB1, CT2 corresponds to CB2, CT3 corresponds to CB3, CT4 corresponds to CB4), and outputs the corresponding Sensing signal SS to SEL-487B relay. Here, the sensing signal SS can make the SEL-487B relay output corresponding signal 87Z1 or signal 87Z2 (Figure 1B).

The SEL-487B relay is electrically connected to the circuit breaker CB0, the first circuit breaker CB1, CB3, and the second circuit breaker CB2, CB4 (not shown). Among them, the signal 87Z1 output by the SEL-487B electrical relay can control the connecting circuit breaker CB0 and the first circuit breakers CB1, CB3; the signal 87Z2 output by the SEL-487B electrical relay can control the connecting circuit breaker CB0 and the second circuit breakers CB2, CB4. Here, “control” the circuit breaker means that when the signal is 1, for example, the switch that can control the circuit breaker is switched off (opens, isolates the fault), and the current cannot pass through the circuit breaker; on the contrary, when the signal is 0, then The switch of the circuit breaker cannot be controlled to switch off (open), and current can pass through the circuit breaker. The SEL-487B relay has a protection relay logic to determine whether the output signal 87Z1 or 87Z2 is 1. Specifically, when the signal 87Z1 is 1, the equipment connected to the first bus #1 BUS is isolated from the first bus #1 BUS through a circuit breaker; and when the signal 87Z2 is 1, it is connected to the second bus #2 BUS The connected equipment is isolated from the second bus #2 BUS through a circuit breaker to isolate the fault.

According to the different parameters, the current SEL-487B electrical relay used in Taipower’s 161kV system can be divided into the new and old versions. The following first discusses the possible problems of the protection relay logic planning before the improvement of the new and old versions, and then explains the improved protection relay logic (the new protection relay logic is the improved protection Electrical station logic).

Since the protection relay logic planning of the first zone (Zone 1) and the second zone (Zone 2) of the dual-bus power system 1 is consistent, the following only takes the logic of the first zone (Zone 1) as an example for description. It is understandable that the first zone (Zone 1) and the second zone (Zone 2) are respectively electrically connected to the SEL-487B relay and correspond to the control zones (devices) of the signals 87Z1 and 87Z2. If a fault occurs in the first zone (Zone 1), the SEL-487B relay will send a signal 87Z1 (for example, 1) to trip the circuit breaker of the corresponding Zone 1, thereby isolating the fault; if the second zone (Zone 2) When a fault occurs, the SEL-487B relay sends a signal 87Z2 (for example, 1) to trip the circuit breaker of the corresponding Zone 2, thereby isolating the fault. The first zone (Zone 1) and the second zone (Zone 2) are specific terms for the dual-bus power system 1 in FIG. 1A, and those skilled in the art should understand their meaning.

Fig. 2 is a schematic diagram of the logical planning of the first area of the old version of the SEL-487B electrical relay in the dual-bus power system of Fig. 1A.

Please refer to Figure 2 and the following equations (1) to (3) for the logic plan of the Zone 1 part of the old SEL-487B relay. In Figure 2, the signal IOP1 is the absolute value of the sum of the currents flowing into and out of the zone 1 protection zone, and the signal IRT1 is the absolute value of the sum of the currents flowing into and out of the zone 1 protection zone; the signal 87Z1 is the absolute value of the zone 1 Monitoring signal (control signal), whether the action depends on whether signal 87R1 and signal Z1S are both at the same time. The signal 87R1 is determined by the signal FDIF1, the signal 87O1 and the signal FAULT1. Among them, the signal FDIF1 is to judge whether the operating point is located in the action area, that is, IOP1>IRT1×SLP1 (if it is judged that it may be an external fault, SLP1 will switch to SLP2); the signal 87O1 is to judge whether the action amount of the signal IOP1 is greater than the setting The signal is O87P; the signal FAULT1 is to judge whether it is an internal fault. The signal Z1S is determined by the signal PLT12 and the signal PCT06Q, where the signal PLT12 is whether the US/LK switch is used on site (that is, the safety lock switch, when it is used, it is 1); the signal PCT06Q is whether the Zone 3 component of the station is operating (That is, Zone 1 plus Zone 2 is regarded as a node, and its working point will act if it is in the working area).

In addition, it can be observed from Figure 2 and Equation (2) that in the old logic plan, E87SSUP=N, that is, when CT Failure occurs, the 87B protection function of the relay is not blocked. 87 1 = 87R1 × Z1S (1) 87𝑅1 = FDIF1 × 87O1 × FAULT1 (2) 𝑍1𝑆 = 𝑃𝐿𝑇12 × PCT06Q (3)

Fig. 3 is a schematic diagram of the logical planning of the first area of the new version of the SEL-487B electrical relay in the dual-bus power system of Fig. 1A.

Please refer to Figure 3 for the logic plan of Zone 1 of the new version of SEL-487B relay. Compared with the old version of logic, the new version of signal 87R1 and signal Z1S are changed as follows: 87𝑅1 = FDIF1 × 87O1 × FAULT1 × 87ST1 reverse signal (4) 𝑍1𝑆 = PLT12 × OCTZ1 reverse signal × 87CZ1 (5)

It can be seen from Fig. 3 that E87SSUP=Y, that is, it is judged whether CT Failure occurs by whether the amount of motion of the signal IOP1 is greater than that of the signal S87P. In addition, in the part of the signal Z1S, the signal 87CZ1 and the signal OCTZ1 are signals (or components) that are only available in the new version of the SEL-487B electrical relay. Among them, the signal 87CZ1 is to determine whether the Check Zone is active, and the signal OCTZ1 is another component to determine whether a CT Failure occurs. The logic can be shown in Figure 4.

In Figure 4, the action of the signal OCTZ1 must meet the following four conditions: ∆𝐼𝑂𝑃1𝑅 ＞ 0.05 (6) ∆𝐼𝑂𝑇1𝑅 <−0.05 (7) ∆𝐼𝑂𝑃1𝑅 + ∆𝐼𝑂𝑇1𝑅 ＜ 0.05 ❑ ❯ (8) 𝐼𝑂𝑃1 ＞ 𝑆87𝑃 (set to 0.1) (9)

The reset conditions of the signal OCTZ1 are as follows, and one of the conditions is fulfilled to reset: 𝐼𝑂𝑃1 <0.9 × 𝑆87𝑃 (10) 𝐼𝑂𝑃1 <0.05 (11)

| = 0                                      (12) 𝐼𝑅𝐸1 =

= 2                                        (13) In addition, FIG. 5 is a schematic diagram of the dual busbar power system 1 of FIG. 1A when no current comparator abnormality occurs (the currents I1 to I6 shown in FIG. 5 are simulated values used for calculation, not actual values). Taking Figure 5 as an example, when CT Failure does not occur during normal operation, the amount of action of the signal IOP1 and the amount of suppression of the signal IRT1 of Zone 1 are: 𝐼𝑂𝑃1 = |

| = 0 (12) 𝐼𝑅𝐸1 =

= 2 (13)

| = 1                                       (14) 𝐼𝑅𝐸1 =

= 1                                            (15) In addition, FIG. 6 is a schematic diagram of the double busbar power system 1 of FIG. 1A when an abnormality of the current ratio occurs. Taking Figure 6 as an example, if CT Failure (CT OPEN) occurs in the current I1, the activity amount of the signal IOP1 of Zone 1 and the suppression amount of the signal IRT1 are respectively: 𝐼𝑂𝑃1 = |

| = 1 (14) 𝐼𝑅𝐸1 =

= 1 (15)

From equation (12) to equation (15), the changes in the amount of action and suppression can be calculated as follows: ∆𝐼𝑂𝑃1𝑅 = 1 − 0 = 1 (16) ∆𝐼𝑅𝐸1 = 1 − 2 = −1 (17)

Applying the above results to the conditions of equations (6) to (9), equations (18) to (21) can be obtained, which meet the operating conditions of the signal OCTZ1 to block the protection function of 87B. ∆𝐼𝑂𝑃1𝑅 = 1 ＞ 0.05 (18) ∆𝐼𝑂𝑇1𝑅 = −1 ＜ -0.05 (19) ∆𝐼𝑂𝑃1𝑅 + ∆𝐼𝑂𝑇1𝑅 = 1 − 1 = 0 ＜ 0.05 (20) 𝐼𝑂𝑃1 = 1 ＞ 𝑆87𝑃 = 0.1 (21)

If the condition of CT Failure is removed later, the amount of action and suppression will be restored from the calculated values of equations (14) and (15) to the calculated values of equations (12) and (13), meeting the condition of reset signal OCTZ1, As shown in equations (22) and (23). 𝐼𝑂𝑃1 = 0 ＜ 0.9 × 𝑆87𝑃 = 0.09 (22) 𝐼𝑂𝑃1 = 0 <0.05 (23)

The following are respectively for (1), CT Failure occurred under normal operation; (2), External failure occurred after Zone 2 CT Failure; (3), First bus #1 BUS failure occurred after the second bus #2 BUS was deactivated And so on, to analyze the logic weakness of the new and old SEL-487B electrical relays.

(1) CT Failure occurs under normal operation:

It can be seen from Figure 2 and Figure 3 that the new version of the SEL-487B relay is related to the signal OCTZ1 and the signal 87ST1 due to the 87Z1 signal. When a CT Failure occurs, the signal OCTZ1 will act and block 87Z1. At the same time, if the signal IOP1 is greater than the set value of the signal S87P, after the set time (87STPU), the signal 87ST1 will also be established and 87Z1 will be blocked. In contrast to the old version of SEL-487B relay logic, except for the no signal OCTZ1 parameter, because E87SSUP is set to N, the signal 87Z1 and 87ST1 have nothing to do with each other. Therefore, when a CT Failure occurs, the protection function will not be blocked.

(2) An external failure occurs after Zone 2 CT Failure:

| = 4                                     (24) 𝐼𝑅𝐸1 =

= 4                                          (25) 𝐼𝑂𝑃1 ＞ 𝑆𝐿𝑃2 × 𝐼𝑅𝐸1 = 0.8 × 4 = 3.2            (26) FIG. 7 is a schematic diagram of the circuit when an external fault occurs after an abnormality of the current converter occurs in the dual busbar power system 1 of FIG. 1A. As shown in Figure 7, it is a situation where an external failure occurs after CT Failure. From the current value in the figure, we can get: 𝐼𝑂𝑃1 = |

| = 4 (24) 𝐼𝑅𝐸1 =

= 4 (25) 𝐼𝑂𝑃1 ＞ 𝑆𝐿𝑃2 × 𝐼𝑅𝐸1 = 0.8 × 4 = 3.2 (26)

Please refer to Figure 3 again. In this case, the new version of the SEL-487B relay will be blocked due to the establishment of the signal OCTZ1 and the signal 87ST1 due to the 87B1 protection function. However, the old version of the SEL-487B relay was set to N due to E87SSUP, the signal 87ST1 was established, but the signal 87Z1 could not be blocked, and the old version did not have the signal OCTZ1, resulting in an external failure in the case of CT Failure, 87B Zone 2 would operate. As shown in Figure 2 and equation (26).

(3) The first bus #1 BUS failure occurs after the second bus #2 BUS is disabled:

| = 0                           (27) 𝐼𝑅𝐸1 _{𝑛𝑜𝑟𝑚𝑎𝑙}=

= 1.6                           (28) 𝐼𝑂𝑃2 _{𝑛𝑜𝑟𝑚𝑎𝑙}= |

| = 0                            (29) 𝐼𝑅𝐸2 _{𝑛𝑜𝑟𝑚𝑎𝑙}=

= 1.6                           (30) FIG. 8 is a schematic diagram of the circuit in the dual busbar power system 1 of FIG. 1A during normal operation. The general normal operation is shown in Figure 8. The amount of action and inhibition are as follows: 𝐼𝑂𝑃1 _{𝑛𝑜𝑟𝑚𝑎𝑙} = |

| = 0 (27) 𝐼𝑅𝐸1 _{𝑛𝑜𝑟𝑚𝑎𝑙} =

= 1.6 (28) 𝐼𝑂𝑃2 _{𝑛𝑜𝑟𝑚𝑎𝑙} = |

| = 0 (29) 𝐼𝑅𝐸2 _{𝑛𝑜𝑟𝑚𝑎𝑙} =

= 1.6 (30)

| = 0.2                        (31) 𝐼𝑅𝐸1 _{#2 𝐵𝑈𝑆 𝑆𝑇𝑂𝑃}=

= 1.4                           (32) 𝐼𝑂𝑃2 _{#2 𝐵𝑈𝑆 𝑆𝑇𝑂𝑃}= |

| = 0.2                         (33) 𝐼𝑅𝐸2 _{#2 𝐵𝑈𝑆 𝑆𝑇𝑂𝑃}=

= 1.4                           (34) 𝐼𝑂𝑃1 ＜ 𝑆𝐿𝑃1 × 𝐼𝑅𝐸1 = 0.6 × 1.4 = 0.84       (35) 𝐼𝑂𝑃2 ＜ 𝑆𝐿𝑃1 × 𝐼𝑅𝐸2 = 0.6 × 1.4 = 0.84       (36) FIG. 9 is a schematic diagram of the circuit when the second bus bar is disabled in the dual-bus power system 1 of FIG. 1A. If the second busbar #2 BUS needs power outage maintenance and other works, change its power supply and load to the first busbar #1 BUS for operation, as shown in Figure 9. At this time, a differential current may be generated. Its IOP1 and IRT1 are as shown in equations (31) to (34), and from equations (35) and (36), it can be known that 87B1 and 87B2 actions will not be caused in this case. 𝐼𝑂𝑃1 _{#2 𝐵𝑈𝑆 𝑆𝑇𝑂𝑃} = |

| = 0.2 (31) 𝐼𝑅𝐸1 _{#2 𝐵𝑈𝑆 𝑆𝑇𝑂𝑃} =

= 1.4 (32) 𝐼𝑂𝑃2 _{#2 𝐵𝑈𝑆 𝑆𝑇𝑂𝑃} = |

| = 0.2 (33) 𝐼𝑅𝐸2 _{#2 𝐵𝑈𝑆 𝑆𝑇𝑂𝑃} =

= 1.4 (34) 𝐼𝑂𝑃1 ＜ 𝑆𝐿𝑃1 × 𝐼𝑅𝐸1 = 0.6 × 1.4 = 0.84 (35) 𝐼𝑂𝑃2 ＜ 𝑆𝐿𝑃1 × = 0.84 (0.84)1.4

| = 3.4                      (37) 𝐼𝑅𝐸1 _{#2 𝐵𝑈𝑆 𝑆𝑇𝑂𝑃}=

= 4.6                       (38) 𝐼𝑂𝑃2 _{#2 𝐵𝑈𝑆 𝑆𝑇𝑂𝑃}= |

| = 3.2                      (39) 𝐼𝑅𝐸2 _{#2 𝐵𝑈𝑆 𝑆𝑇𝑂𝑃}=

= 4.8                        (40) 𝐼𝑂𝑃1 ＞ 𝑆𝐿𝑃1 × 𝐼𝑅𝐸1 = 0.6 × 4.6 = 2.76       (41) 𝐼𝑂𝑃2 ＞ 𝑆𝐿𝑃1 × 𝐼𝑅𝐸2 = 0.6 × 4.8 = 2.88       (42) 10 is a schematic circuit diagram of the first busbar failure when the second busbar is disabled in the dual busbar power system 1 of FIG. 1A. If the first bus #1 BUS fails when the second bus #2 BUS is disabled, the schematic diagram of the current is shown in FIG. 10. From equation (37) to equation (42), it can be seen that in this case, the 87B1 and 87B2 of the old SEL-487B relay will act to isolate the fault; the new SEL-487B relay is because the second bus #2 BUS stops. After use and deactivation, OCTZ1, OCTZ2, 87ST1 or 87ST2 is established and the functions of 87B1 and 87B2 are blocked. 𝐼𝑂𝑃1 _{#2 𝐵𝑈𝑆 𝑆𝑇𝑂𝑃} = |

| = 3.4 (37) 𝐼𝑅𝐸1 _{#2 𝐵𝑈𝑆 𝑆𝑇𝑂𝑃} =

= 4.6 (38) 𝐼𝑂𝑃2 _{#2 𝐵𝑈𝑆 𝑆𝑇𝑂𝑃} = |

| = 3.2 (39) 𝐼𝑅𝐸2 _{#2 𝐵𝑈𝑆 𝑆𝑇𝑂𝑃} =

= 4.8 (40) 𝐼𝑂𝑃1 ＞ 𝑆𝐿𝑃1 × 𝐼𝑅𝐸1 = 0.6 × 4.6 = 2.76 (41) 𝐼𝑂𝑃2 ＞ 𝑆𝐿1 = 0.6 × 88 × 42 4.8

It can be seen from the above that the protection logic of the new and old SEL-487B electrical relays needs to be addressed as follows: the old SEL-487B electrical relay has an external failure under the condition of CT Failure, which causes the 87B electrical relay to operate multiple times; the new SEL-487B electrical relay The 87B1 and 87B2 functions will be blocked during the single bus deactivation process or after the station is deactivated and cannot operate correctly.

Therefore, this new model proposes the following logic plans for the new and old SEL-487B electrical relays, so as to improve the above-mentioned weaknesses of the new and old SEL-487B electrical relays, and at the same time make the logic of the new and old SEL-487B electrical relays consistent .

FIG. 11 is a schematic diagram of the protection relay logic of Zone 1 of the old version SEL-487B relay after the improvement of an embodiment of the new type. As shown in Figure 11, the improved protection relay logic Lo of the old version of the SEL-487B relay includes a first and gate 11 and a second and gate 12. In addition, the protection relay logic Lo of this embodiment may further include a third and gate 13, a selection element 14, a judgment element 15, a first comparator 16, a second comparator 17, and a delay action element 18. .

The first and gate 11 has three first input terminals and a first output terminal, one of the first input terminals is connected to the signal PLT12, the other of the first input terminals is connected to the signal PCT06Q, the first inputs One of the terminals is connected to the reverse signal 87ST3 (that is, the reverse signal of signal 87ST3).

The second sum gate 12 has two second input terminals and a second output terminal, one of the second input terminals is connected to the first output terminal of the first sum gate 11, and the other of the second input terminals is connected Signal 87R1 (this embodiment is applied to Zone 1, so it is signal 87R1; when applied to Zone 2, it is signal 87R2), and the second output end outputs signal 87Z1 (this embodiment is applied to Zone 1, so it is Signal 87Z1; when used in Zone 2, it is signal 87Z2).

The third and gate 13 has four third input terminals and a third output terminal, one of the third input terminals is connected to the output terminal of the judgment element 15, and the other of the third input terminals is connected to the first comparator 16 is the output terminal, and one of the third input terminals is connected to the signal FAULT1 (this embodiment is applied to Zone 1, so it is the signal FAULT1; when applied to Zone 2, it is the signal FAULT2), and the component 14 is selected The inverted signal of the output signal of the output terminal is input to one of the third input terminals of the third and gate 13 (that is, the fourth of the third input terminals), and the output terminal of the third and gate 13 outputs the signal 87R1 (this embodiment is applied to Zone 1, so it is signal 87R1; when applied to Zone 2, it is signal 87R2).

It is determined that one of the input terminals of the element 15 is connected to the signal IRT1 (this embodiment is applied to Zone 1, so it is the signal IRT1; when applied to Zone 2, it is the signal IRT2), and the other of the input terminals of the element 15 is judged to be connected The signal IOP1 (this embodiment is applied to Zone 1, so it is the signal IOP1; when applied to Zone 2, it is the signal IOP2).

One of the input terminals of the first comparator 16 is connected to the signal IOP1 (this embodiment is applied to Zone 1, so it is the signal IOP1; when applied to Zone 2, it is the signal IOP2), and the input terminal of the first comparator 16 is The other is connected to the signal O87P, and the signal output by the first comparator 16 is input to the third AND gate 13. One of the input terminals of the second comparator 17 is connected to the signal IOP1 (this embodiment is applied to Zone 1, so it is the signal IOP1; when applied to Zone 2, it is the signal IOP2), and the other of its input terminals is connected to the signal S87P, the output terminal of the second comparator 17 outputs a signal 87S1 (this embodiment is applied to Zone 1, so it is signal 87S1; when applied to Zone 2, it is signal 87S2).

The input terminal of the delay action element 18 is connected to the output terminal of the second comparator 17, one of the input terminals of the selection element 14 is connected to the output terminal of the delay action element 18, and the other of the input terminals of the selection element 14 is connected to a ground terminal. (N).

In addition, FIG. 12 is a logical schematic diagram of the protection relay of Zone 1 of the improved new version of the SEL-487B relay according to an embodiment of the new type. As shown in FIG. 12, the protection relay logic Ln of the improved new version of the SEL-487B relay includes a first and gate 11, a second and gate 12, a third and gate 13, and a selection element 14. In addition, the protection relay logic Ln of this embodiment may further include a judging element 15, a first comparator 16, a second comparator 17 and a delay action element 18.

The first and gate 11 has three first input terminals and a first output terminal. One of the first input terminals is connected to the signal PLT12, and the other of the first input terminals is connected to the reverse signal 87STCZ1 (ie, the signal The reverse signal of 87STCZ1), one of the first input terminals is connected to the signal 87CZ1.

The second sum gate 12 has two second input terminals and a second output terminal, one of the second input terminals is connected to the first output terminal of the first sum gate 11, and the other of the second input terminals is connected Signal 87R1 (this embodiment is applied to Zone 1, so it is signal 87R1; when applied to Zone 2, it is signal 87R2), the second output terminal of the second and gate 12 outputs signal 87Z1 (this embodiment is applied to Zone 1, so it is signal 87Z1; when applied in Zone 2, it is signal 87Z2).

The third and gate 13 has four third input terminals and a third output terminal. One of the third input terminals is connected to the signal FDIF1 (this embodiment is applied to Zone 1, so it is the signal FDIF1; when applied in Zone 2 is the signal FDIF2), the other of the third input terminals is connected to the signal 87O1 (this embodiment is applied to Zone 1, so it is the signal 87O1; when applied to Zone 2, it is the signal 87O2), One of the third input terminals of the tripod 13 is connected to the signal FAULT1 (this embodiment is applied to Zone 1, so it is the signal FAULT1; when applied to Zone 2, it is the signal FAULT2), select the output of the component 14 The inverted signal of the output signal of the third and gate 13 is input to one of the third input terminals of the third input terminal (that is, the fourth of the third input terminals), and the output terminal of the third and gate 13 outputs the signal 87R1 (this embodiment is applied to Zone 1, so it is signal 87R1; when applied to Zone 2, it is signal 87R2).

It is determined that one of the input terminals of the element 15 is connected to the signal IRT1 (this embodiment is applied to Zone 1, so it is the signal IRT1; when applied to Zone 2, it is the signal IRT2), and the other of the input terminals of the element 15 is judged to be connected The signal IOP1 (this embodiment is applied to Zone 1, so it is the signal IOP1; when applied to Zone 2, it is the signal IOP2), the output terminal of the judging element 15 outputs the signal FDIF1 (this embodiment is applied to Zone 1, so It is the signal FDIF1; when used in Zone 2, it is the signal FDIF2).

One of the input terminals of the first comparator 16 is connected to the signal IOP1 (this embodiment is applied to Zone 1, so it is the signal IOP1; when applied to Zone 2, it is the signal IOP2), and the input terminal of the first comparator 16 is The other is connected to the signal O87P, and the output terminal of the first comparator 16 outputs the signal 87O1 (this embodiment is applied to Zone 1, so it is signal 87O1; when applied to Zone 2, it is signal 87O2).

One of the input terminals of the second comparator 17 is connected to the signal IOP1 (this embodiment is applied to Zone 1, so it is the signal IOP1; when applied to Zone 2, it is the signal IOP2), and the input of the second comparator 17 The other one of the terminals is connected to the signal S87P.

The input terminal of the delay action element 18 is connected to the output terminal of the second comparator 17, one of the input terminals of the selection element 14 is connected to the output terminal of the delay action element 18, and the other of the input terminals of the selection element 14 is connected to the ground terminal ( N). In this embodiment, the output terminal of the selection element 14 is directly connected to the ground terminal (N).

From the above content and Figure 11, Figure 12 we can see. In order to make the logic of the new and old SEL-487B electrical relays consistent and to solve the above-mentioned weaknesses of the new and old SEL-487B electrical relays, the logic changes of the new and old SEL-487B electrical relays are as follows: the old version of Figure 11 The E87SSUP of the SEL-487 relay remains grounded (E87SSUP = N), but the first and gate 11 has a new input terminal, and the reverse signal of 87ST3 is added to the input terminal; and the new version of SEL-487B in Figure 12 The relay set E87SSUP to ground (E87SSUP = N), and the input signal of the first and gate 11 is changed from OCTZ1 to 87STCZ1 (the OCTZ1 of Z1S and OCTZ2 of Z2S are both modified to 87STCZ1). Among them, the parameter functions of 87ST3 and 87STCZ1 are the same. Both are the sum of the currents flowing into and out of the bus. The names are only different due to different versions.

Situational analysis after improvement:

(1) An external failure occurs after Zone 2 CT Failure:

Old version of SEL-487B electric station:

| = 4          (43) 𝐼𝑂𝑃3𝐶𝑇 𝑂𝑃𝐸𝑁_𝑒𝑥 ＞ 𝑆87(= 0.1)                       (44) Referring to the current situation in Figure 7, the available signal IOP3 is: 𝐼𝑂𝑃3𝐶𝑇 𝑂𝑃𝐸𝑁_𝑒𝑥 = |

| = 4 (43) 𝐼𝑂𝑃3𝐶𝑇 𝑂𝑃𝐸𝑁_𝑒𝑥 ＞ 𝑆87(= 0.1) (44)

Because IOP3>S87P, 87ST3 is established and Z1S and Z2S are blocked, so 87B2 will not operate much.

The new version of SEL-487B electric station:

| = 4     (45) 𝐼𝑂𝑃𝐶𝑍1𝐶𝑇 𝑂𝑃𝐸𝑁_𝑒𝑥 ＞ 𝐶𝑍𝑆87(= 0.1)            (46) Referring to the current situation in Figure 7, the IOPCZ1 can be obtained as: 𝐼𝑂𝑃𝐶𝑍1𝐶𝑇 𝑂𝑃𝐸𝑁_𝑒𝑥 = |

| = 4 (45) 𝐼𝑂𝑃𝐶𝑍1𝐶𝑇 𝑂𝑃𝐸𝑁_𝑒𝑥 ＞ 𝐶𝑍𝑆87(= 0.1) (46)

Because IOPCZ1>CZS87P, the signal 87STCZ1 is established and the signals Z1S and Z2S are blocked, so 87B2 will not move much.

(2) The first bus #1 BUS failure occurs after the second bus #2 BUS is disabled:

Old version of SEL-487B electric station:

| = 0          (47) 𝐼𝑂𝑃3#2 𝐵𝑈𝑆 𝑆𝑇𝑂𝑃 ＜ 𝑆87(= 0.1)                     (48) Refer to the current situation in Figure 9 to get the IOP3 of the second bus #2 BUS disabled but the first bus #1 BUS failure situation: 𝐼𝑂𝑃3#2 𝐵𝑈𝑆 𝑆𝑇𝑂𝑃 = |

| = 0 (47) 𝐼𝑂𝑃3#2 𝐵𝑈𝑆 𝑆𝑇𝑂𝑃 ＜ 𝑆87(= 0.1) (48)

| = 3.4                     (49) 𝐼𝑅𝐸1#2 𝐵𝑈𝑆 𝑆𝑇𝑂𝑃 =

= 4.6                        (50) 𝐼𝑂𝑃1 ＞ 𝑆𝐿𝑃1 × 𝐼𝑅𝐸1 = 0.6 × 4.6 = 2.76           (51) 𝐼𝑂𝑃3#2 𝐵𝑈𝑆 𝑆𝑇𝑂𝑃 = |

| = 3.2                      (52) 𝐼𝑅𝐸1#2 𝐵𝑈𝑆 𝑆𝑇𝑂𝑃 =

= 4.8                         (53) 𝐼𝑂𝑃1 ＞ 𝑆𝐿𝑃1 × 𝐼𝑅𝐸1 = 0.6 × 4.8 = 2.88            (54) At the moment when the first bus #1 BUS fails, 87ST3 is not established, so 87B1 and 87B2 are not blocked. Referring to the current situation in Fig. 10, IOP1 and IOP2 of the first bus #1 BUS failure condition after the second bus #2 BUS is disabled, as shown in equations (49) to (54), because the protection function has not been Blocked, so the relay can still operate normally to isolate the fault. 𝐼𝑂𝑃1#2 𝐵𝑈𝑆 𝑆𝑇𝑂𝑃 = |

| = 3.4 (49) 𝐼𝑅𝐸1#2 𝐵𝑈𝑆 𝑆𝑇𝑂𝑃 =

= 4.6 (50) 𝐼𝑂𝑃1 ＞ 𝑆𝐿𝑃1 × 𝐼𝑅𝐸1 = 0.6 × 4.6 = 2.76 (51) 𝐼𝑂𝑃3#2 𝐵𝑈𝑆 🝑

| = 3.2 (52) 𝐼𝑅𝐸1#2 𝐵𝑈𝑆 𝑆𝑇𝑂𝑃 =

= 4.8 (53) 𝐼𝑂𝑃1 ＞ 𝑆𝐿𝑃1 × 𝐼𝑅𝐸1 = 0.6 × 4.8 = 2.88 (54)

New version of SEL-487B:

| = 0      (55) 𝐼𝑂𝑃𝐶𝑍1#2 𝐵𝑈𝑆 𝑆𝑇𝑂𝑃 ＜ 𝐶𝑍𝑆87(= 0.1)            (56) Referring to the current situation in Figure 9, we can get the IOPCZ1 of the second bus #2 BUS disabled but the first bus #1 BUS failure condition: 𝐼𝑂𝑃𝐶𝑍1#2 𝐵𝑈𝑆 𝑆𝑇𝑂𝑃 = |

| = 0 (55) 𝐼𝑂𝑃𝐶𝑍1#2 𝐵𝑈𝑆 𝑆𝑇𝑂𝑃 ＜ 𝐶𝑍𝑆87(= 0.1) (56)

| = 3.4                     (57) 𝐼𝑅𝐸1#2 𝐵𝑈𝑆 𝑆𝑇𝑂𝑃 =

= 4.6                        (58) 𝐼𝑂𝑃1 ＞ 𝑆𝐿𝑃1 × 𝐼𝑅𝐸1 = 0.6 × 4.6 = 2.76           (59) 𝐼𝑂𝑃3#2 𝐵𝑈𝑆 𝑆𝑇𝑂𝑃 = |

| = 3.2                     (60) 𝐼𝑅𝐸1#2 𝐵𝑈𝑆 𝑆𝑇𝑂𝑃 =

= 4.8                         (61) 𝐼𝑂𝑃1 ＞ 𝑆𝐿𝑃1 × 𝐼𝑅𝐸1 = 0.6 × 4.8 = 2.88            (62) At the moment when the first bus #1 BUS fails, 87STCZ1 is not established, so 87B1 and 87B2 are not blocked. Referring to the current situation in Fig. 10, IOP1 and IOP2 of the first bus #1 BUS failure condition after the second bus #2 BUS is disabled, as shown in equations (57) to (62), because the protection function has not been Blocked, so the relay can still operate normally to isolate the fault. 𝐼𝑂𝑃1#2 𝐵𝑈𝑆 𝑆𝑇𝑂𝑃 = |

| = 3.4 (57) 𝐼𝑅𝐸1#2 𝐵𝑈𝑆 𝑆𝑇𝑂𝑃 =

= 4.6 (58) 𝐼𝑂𝑃1 ＞ 𝑆𝐿𝑃1 × 𝐼𝑅𝐸1 = 0.6 × 4.6 = 2.76 (59) 𝐼𝑂𝑃3#2 𝐵𝑈𝑆 🝑

| = 3.2 (60) 𝐼𝑅𝐸1#2 𝐵𝑈𝑆 𝑆𝑇𝑂𝑃 =

= 4.8 (61) 𝐼𝑂𝑃1 ＞ 𝑆𝐿𝑃1 × 𝐼𝑅𝐸1 = 0.6 × 4.8 = 2.88 (62)

In order to make the simulation results more in line with the actual operating conditions, the new model uses the Real Time Digital Simulator (RTDS) developed by RTDS Technologies to build an analysis model based on the actual system parameters, and performs on-site playback tests to confirm the above logic Whether the modification can solve the blind spots of the protection logic of the new and old versions of SEL-487 relays. Here, the test scenario is as follows: (1) 6.5 seconds after the second bus #2 BUS power failure, the first bus #1 BUS failure occurs; (2) 6 seconds after CT Failure, an external failure occurs. In scenario (1), when the first bus #1 BUS failure occurs, both signal 87Z1 and signal 87Z2 can act to eliminate the fault. In Scenario (2), the protection function can indeed be blocked, so the relay will not operate when an external fault occurs.

It can be seen that the improved protection relay logic Lo and Ln of the new and old versions of SEL-487 relays proposed in this article can not only improve the existing new, The blind spots of the protection logic of the old version of SEL-487 electrical relays also make the protection logic of the new and old SEL-487B electrical relays consistent.

The revised logic plan of the new and old SEL-487B electrical relays proposed in this article has been applied to all the SEL-487B electrical relays of Taipower’s 161kV power system at the end of December 2018. The actual system has been operating for more than 1 year without exception. In the actual accident case part, in 2020, a substation carried out a power outage inspection of the busbar equipment, and the power outage busbar failed when the work was completed and the power was restored. This is exactly the situation considered in the improvement logic of this article, showing that any probability is small Failure scenarios still have a chance to occur. The SEL-487B busbar protection relay of this accident immediately tripped and isolated the fault, and once again verified the correctness of the new logic after the improvement of this article.

To sum up, in the protection relay logic of the dual-bus power system with connected circuit breakers and the dual-bus power system applying the protection relay logic of the present invention, the above-mentioned logic planning can improve the existing version The blind spot of the protection logic of the SEL-487B electrical relay also makes the protection logic of the existing version of the SEL-487B electrical relay consistent, which in turn enables the dual-bus power system with connected circuit breakers to provide stable power supply.

The above descriptions are merely illustrative and not restrictive. Any equivalent modifications or changes that do not depart from the spirit and scope of this new model shall be included in the scope of the attached patent application.

1: Double busbar power system 11: First and gate 12: Second and gate 13: Third and gate 14: Select components 15: Judgment component 16: first comparator 17: The second comparator 18: Delay action element 87CZ1, 87O1, 87R1, 87S1, 87ST, 87ST1, 87ST3, 87STCZ1, 87Z1, 87Z2, FAULT1, FDIF1, IOP1, IRT1, O87P, OCTZ1, PCT06Q, PLT12, S87P, Z1S, △IOPIR: Signal CB0: Contact circuit breaker CB1, CB3: the first circuit breaker CB2, CB4: second circuit breaker CT0, CT0’, CT1～CT4: Current ratio device DS1～DS4: Isolating switch I1～I6: current Lo, Ln: protection relay logic L1, S1: the first power equipment L2, S2: second power equipment SS: Sensing signal #1 BUS: The first bus #2 BUS: The second bus

FIG. 1A is a schematic diagram of the structure of a dual-bus-bar power system with a connected circuit breaker according to an embodiment of the new type. Figure 1B is a functional block diagram of the SEL-487B relay. Fig. 2 is a schematic diagram of the logical planning of the first area of the old version of the SEL-487B electrical relay in the dual-bus power system of Fig. 1A. Fig. 3 is a schematic diagram of the logical planning of the first area of the new version of the SEL-487B electrical relay in the dual-bus power system of Fig. 1A. Figure 4 is a schematic diagram of the signal OCTZ1. FIG. 5 is a schematic diagram of the circuit in the dual busbar power system 1 of FIG. 1A when no abnormality of the current converter occurs. FIG. 6 is a schematic diagram of the circuit when an abnormality of the current converter occurs in the dual busbar power system 1 of FIG. 1A. Fig. 7 is a schematic diagram of the circuit when an external fault occurs after an abnormality of the current converter occurs in the dual-bus power system 1 of Fig. 1A. FIG. 8 is a schematic diagram of the circuit in the dual busbar power system 1 of FIG. 1A during normal operation. 9 is a schematic diagram of the circuit when the second bus is disabled in the dual-bus power system 1 of FIG. 1A. FIG. 10 is a schematic circuit diagram of the first busbar failure when the second busbar is disabled in the dual busbar power system 1 of FIG. 1A. FIG. 11 is a schematic diagram of the protection relay logic in the first area of the improved old SEL-487B relay according to an embodiment of the new type. FIG. 12 is a logical schematic diagram of the protection relay in the first area of the improved new version of the SEL-487B relay according to an embodiment of the new type.

87Z1, 87Z2: signal

CB0: Contact circuit breaker

CB1, CB3: the first circuit breaker

CB2, CB4: second circuit breaker

CT0, CT0’, CT1~CT4: Current ratio device

DS1~DS4: Isolating switch

L1, S1: the first power equipment

L2, S2: second power equipment

#1 BUS: The first bus

#2 BUS: The second bus

Claims (11)

A protection relay logic for a dual-bus bar power system with a connected circuit breaker. The dual-bus bar power system includes a first bus bar, a second bus bar, the connected circuit breaker, a first power device, and a second bus bar. Power equipment and a SEL-487B electrical station, the connection circuit breaker is connected between the first bus bar and the second bus bar, and the first power equipment is connected to the first bus bar through a corresponding first circuit breaker , The second power device is connected to the second bus bar through a corresponding second circuit breaker, the SEL-487B electrical relay is electrically connected to the connecting circuit breaker, the first circuit breaker and the second circuit breaker, the SEL A signal 87Z1 output by the 487B electrical relay controls the contact breaker and the first circuit breaker, a signal 87Z2 output by the SEL-487B electrical relay controls the contact breaker and the second circuit breaker; the SEL-487B electrical relay With the protection relay logic, the protection relay logic includes: A first gate has three first input terminals and a first output terminal. One of the first input terminals is connected to a signal PLT12, and the other of the first input terminals is connected to a signal PCT06Q. Another one of the first input terminals is connected to a reverse signal 87ST3; and A second and gate has two second input terminals and a second output terminal. One of the second input terminals is connected to the first output terminal, and the other of the second input terminals is connected to a signal 87R1 or Signal 87R2, and the second output terminal outputs the signal 87Z1 or the signal 87Z2; Wherein, when applied to a first area, the other one of the second input terminals is connected to the signal 87R1, and the second output terminal outputs the signal 87Z1; when applied to a second area, the first The other of the two input terminals is connected to the signal 87R2, and the second output terminal outputs the signal 87Z2. The protection relay logic according to claim 1, wherein the first power device or the second power device is a power source or a load. The protection relay logic described in claim 1 further includes: A judging element, wherein when applied to the first area, one of the input ends of the judging element is connected to a signal IRT1, and the other of its input ends is connected to a signal IOP1; when applied to the second area, the One of the input ends of the judging element is connected to a signal IRT2, and the other of its input ends is connected to a signal IOP2; A first comparator, wherein when applied to the first area, one of the input terminals of the first comparator is connected to a signal IOP1, and the other of its input terminals is connected to a signal O87P; when applied to the second area In the area, one of the input terminals of the first comparator is connected to a signal IOP2, and the other of its input terminals is connected to the signal O87P; and A second comparator, wherein when applied to the first area, one of the input terminals of the second comparator is connected to a signal IOP1, and the other of its input terminals is connected to a signal S87P; when applied to the second area In the area, one of the input terminals of the second comparator is connected to a signal IOP2, and the other of its input terminals is connected to the signal S87P. The protection relay logic described in claim 3 further includes: A delay action element, the input terminal of which is connected to the output terminal of the second comparator; and A selection element, one of its input ends is connected to the output end of the delay action element, and the other of its input ends is connected to a ground. The protection relay logic described in claim 4 further includes: A third and gate has four third input terminals and a third output terminal, one of the third input terminals is connected to the output terminal of the judgment element, and the other of the third input terminals is connected to the first The output terminal of the comparator. One of the third input terminals is connected to a signal FAULT1 or a signal FAULT2. The output terminal of the and gate outputs the signal 87R1 or signal 87R2; Wherein, when applied to the first area, another one of the third input terminals is connected to the signal FAULT1, and the output terminal of the third and gate outputs the signal 87R1; when applied to the second area, the first Another one of the three input terminals is connected to the signal FAULT2, and the output terminal of the third and gate outputs the signal 87R2. A protection relay logic for a dual-bus bar power system with a connected circuit breaker. The dual-bus bar power system includes a first bus bar, a second bus bar, the connected circuit breaker, a first power device, and a second bus bar. Power equipment and a SEL-487B electrical station, the connection circuit breaker is connected between the first bus bar and the second bus bar, and the first power equipment is connected to the first bus bar through a corresponding first circuit breaker , The second power device is connected to the second bus bar through a corresponding second circuit breaker, a signal 87Z1 output by the SEL-487B electrical relay controls the connection circuit breaker and the first circuit breaker, the SEL-487B electrical A signal 87Z2 output by the relay station controls the contact breaker and the second circuit breaker; the SEL-487B relay has the protection relay logic, and the protection relay logic includes: A first and gate, having three first input terminals and a first output terminal, one of the first input terminals is connected to a signal PLT12, and the other of the first input terminals is connected to a signal 87STCZ1 in the opposite direction , One of the first input terminals is connected to a signal 87CZ1; A second and gate has two second input terminals and a second output terminal. One of the second input terminals is connected to the first output terminal, and the other of the second input terminals is connected to a signal 87R1 or Signal 87R2, the second output terminal outputs the signal 87Z1 or the signal 87Z2, wherein when applied to a first zone, the other of the second input terminals is connected to the signal 87R1, and the second output terminal outputs the signal 87Z1; When applied to a second area, the other of the second input terminals is connected to the signal 87R2, and the second output terminal outputs the signal 87Z2; A third and gate has four third input terminals and a third output terminal, one of the third input terminals is connected to a signal FDIF1 or a signal FDIF2, and the other of the third input terminals is connected to a signal 87O1 Or signal 87O2, one of the third input terminals is connected to a signal FAULT1 or signal FAULT2, and the output terminal of the third and gate outputs the signal 87R1 or signal 87R2. When applied to the first area, the signals One of the third input terminals is connected to the signal FDIF1, another of the third input terminals is connected to the signal 87O1, and another of the third input terminals is connected to the signal FAULT1, and the output terminal of the third sum gate outputs the signal Signal 87R1; when applied to the second area, one of the third input terminals is connected to the signal FDIF2, another of the third input terminals is connected to the signal 87O2, and another of the third input terminals is connected For the signal FAULT2, the output terminal of the third and gate outputs the signal 87R2; and A selection element whose output terminal outputs a signal that is reversely input to one of the third input terminals. The protection relay logic according to claim 6, wherein the first power device or the second power device is a power source or a load. The protection relay logic described in claim 6 further includes: A judging element, wherein when applied to the first area, one of the input ends of the judging element is connected to a signal IRT1, the other of its input ends is connected to a signal IOP1, and its output end outputs the signal FDIF1; When in the second area, one of the input ends of the judging element is connected to a signal IRT2, the other of its input ends is connected to a signal IOP2, and its output end outputs the signal FDIF2; A first comparator, wherein when applied to the first area, one of the input terminals of the first comparator is connected to the signal IOP1, the other of the input terminals is connected to a signal O87P, and the output terminal outputs the signal 87O1; when applied to the second area, one of the input terminals of the first comparator is connected to the signal IOP2, the other of its input terminals is connected to the signal O87P, and its output terminal outputs the signal 87O2; and A second comparator, wherein when applied to the first area, one of the input terminals of the second comparator is connected to the signal IOP1, and the other of its input terminals is connected to a signal S87P; when applied to the second area In the area, one of the input terminals of the second comparator is connected to the signal IOP2, and the other of its input terminals is connected to the signal S87P. The protection relay logic described in claim 8 further includes: A delay action element, the input terminal of which is connected to the output terminal of the second comparator; Wherein, one of the input terminals of the selection element is connected to the output terminal of the delay action element, and the other of the input terminals is connected to a ground terminal. The protection relay logic according to claim 9, wherein the output terminal of the selection element is directly connected to the ground terminal. A dual-bus-bar power system, including: A first bus bar and a second bus bar; A connecting circuit breaker connected between the first bus bar and the second bus bar; A first power device is connected to the first bus bar through a corresponding first circuit breaker; A second power device is connected to the second bus bar through a corresponding second circuit breaker; and A SEL-487B electrical relay is electrically connected to the connecting circuit breaker, the first circuit breaker and the second circuit breaker, and a signal 87Z1 output by the SEL-487B electrical relay controls the connecting circuit breaker and the first circuit breaker, A signal 87Z2 output by the SEL-487B relay controls the connecting circuit breaker and the second circuit breaker; Wherein, the SEL-487B relay has the protection relay logic as described in any one of claim items 1 to 10.

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