CN108565835A - Generator relay protecting method and circuit - Google Patents

Abstract

The embodiment of the present invention provides a generator relay protection method and device, which is applied to the scenario where multiple generators are running in parallel in a data center, and the neutral point grounding mode of the multiple generators is single-point grounding through a small resistance , the method includes: obtaining the neutral point side current of the generator; and obtaining the outgoing line side current of the generator; and determining whether the generator is within the protection range according to the neutral point side current, the outgoing line side current and the operating current of the differential current relay failure. Wherein, the current on the neutral point side is the current transformed by the current transformer on the neutral point side of the generator, and the current on the outgoing line side is the current transformed by the current transformer on the outgoing line side of the generator.

Description

Generator relay protection method and circuit

technical field

The embodiments of the present invention relate to the technical field of generators, in particular to a generator relay protection method and circuit.

Background technique

Diesel generators are used more and more widely in data centers, and the generator system of data centers usually uses multiple diesel generators running in parallel. In the case of parallel operation, the neutral point of the diesel generators can be different Grounding, or grounding through a small resistor.

At present, the methods of grounding diesel generators through small resistances include multi-point grounding through small resistances and single-point grounding through small resistances. Multi-point grounding through small resistance means that the neutral point of each generator among multiple generators is grounded through small resistance; single-point grounding through small resistance means that only one generator among multiple generators is grounded The resistance is grounded, and the other generators are not grounded. Taking two diesel generators running in parallel as an example, (a) in Figure 1 is a schematic diagram of multi-point grounding through a small resistance, and (b) in Figure 1 is a schematic diagram of single-point grounding through a small resistance. For the case where the neutral point is single-point grounded through a small resistance, the relay protection of the diesel generator adopts the method of over-current protection. Specifically, it flows into a certain current relay (which can be called current relay 1, and each generator corresponds to a Current relay, the generator corresponding to current relay 1 is called generator 1) The current is the current on the outlet side of the generator, when the current flowing into current relay 1 exceeds the operating current of current relay 1, and when the preset time delay arrives , the current flowing into the current relay 1 still exceeds the operating current of the current relay 1 , the current relay 1 determines that the generator 1 has failed, and the current relay 1 can trigger and cut off the generator 1 .

However, in the above method, when other generators in the data center fail, the current on the outlet side of the generator 1 (that is, the current flowing into the current relay 1) may increase, resulting in a misjudgment that the generator 1 has failed. Therefore, depending on the current on the outgoing side of the generator, it may not be possible to accurately determine whether the generator has failed.

Contents of the invention

The present application provides a generator relay protection method and circuit, which can more quickly and accurately determine a faulty generator and cut off the faulty generator.

In order to achieve the above object, the application adopts the following technical solutions:

In the first aspect, a generator relay protection method is provided, which is applied to the scenario where multiple generators are running in parallel in a data center. The neutral point grounding method of the multiple generators is single-point grounding through a small resistance. The method includes: obtaining the current at the neutral point side of the generator; obtaining the current at the outgoing line side of the generator; and determining whether the generator has a fault within the protection range according to the current at the neutral point side, the outgoing line side current and the operating current of the differential current relay , where the current on the neutral point side is the current transformed by the current transformer on the neutral point side of the generator, and the current on the outgoing line side is the current transformed by the current transformer on the outgoing line side of the generator.

The generator relay protection method provided by this application can determine whether the generator has a fault within the protection range according to the current at the neutral point side, the current at the outgoing line side, and the operating current of the differential current relay. The generators that are not in the protection range are cut off, and the generators that do not have a fault within the protection range are reliably inactive (that is, the generators continue to run). In this way, the faulty generator can be accurately determined and the faulty generator can be cut off.

Furthermore, since the neutral point grounding method of multiple generators running in parallel in the data center is single-point grounding through a small resistance, compared with the multi-point grounding method of generators, when using the single-point grounding method, When the generator fails, the fault current is relatively small, which can reduce the impact on other equipment or distribution lines in the generator system to a certain extent.

In the first optional implementation manner of the first aspect, the operating current of the above-mentioned differential current relay satisfies:

I _dz ＞I _bpmax , and I _dz ≥K× _IN , where I _dz is the operating current of the differential current relay, I _bpmax is the maximum unbalanced current, K is the reliability factor, and I _N is the rated current of the generator.

In this application, the operating current of the differential current relay is greater than the maximum unbalanced current, which can avoid the misoperation of the differential current relay due to the different characteristics of the current transformer on the neutral point side and the current transformer on the outgoing line side due to load changes or external faults , and the operating current of the differential current relay is greater than or equal to K times the rated current, which can prevent the differential current relay from malfunctioning when the current caused by the disconnection of the secondary current loop flows into the differential current relay.

In the second optional implementation manner of the first aspect, the above-mentioned method for determining whether a fault occurs within the protection range of the generator according to the neutral point side current, the outgoing line side current and the operating current of the differential current relay may include: According to the neutral point side current and outgoing line side current, determine the input current of the differential current relay; the direction of the neutral point side current is opposite to that of the outgoing line side current, and the value of the input current of the differential current relay is greater than or equal to the difference When the value of the operating current of the dynamic current relay is determined, it is determined that the generator has a fault within the protection range; the direction of the current at the neutral point side is the same as the direction of the current at the outgoing line side, and the value of the input current of the differential current relay is less than the differential current When the value of the operating current of the relay is checked, it is determined that the generator does not have a fault within the protection range.

In this application, according to the above neutral point side current, outlet side current and differential current relay operating current, it can be determined whether the generator has a fault within the protection range, and only when the generator has a fault within the protection range will it be triggered The relay switch of the differential current relay is closed, thereby triggering and cutting off the generator that has failed. When the generator does not have a fault within the protection range, the differential current relay does not operate, and the generator continues to operate normally.

In the third optional implementation manner of the first aspect, the neutral point side current and the outgoing line side current respectively include three-phase currents, and each phase current of the three-phase currents corresponds to a differential current relay respectively. The method of determining whether the generator has a fault within the protection range may include: according to the current of each phase at the neutral point side and the current of each phase at the outgoing line side, determine The input current of each differential current relay; the direction of the current on the neutral point side is opposite to the direction of the current on the outlet side, and the input of at least one of the three differential current relays corresponding to the three-phase current When the value of the current is greater than or equal to the value of the operating current of the differential current relay, it is determined that the generator has a fault within the protection range; the direction of the current on the neutral point side is opposite to the direction of the current on the outlet side, and it corresponds to the three-phase current When the values of the input currents of the three differential current relays are all smaller than the values of the action currents of the differential current relays, it is determined that no fault within the protection range of the generator has occurred.

In a fourth optional implementation manner of the first aspect, the fact that the generator does not have a fault within the protection range includes that the generator is running normally or the generator has a fault outside the protection range.

In this application, when the generator is running normally or the generator has a fault outside the protection range, the input current of the differential current relay is less than the operating current of the differential current relay, so the differential current relay does not operate, and the generator continues to normal operation.

In the second aspect, the present application provides a generator relay protection circuit, which is applied to the scenario where multiple generators are running in parallel in a data center, and the neutral point grounding method of the multiple generators is single-point grounding through a small resistance , for a generator, the generator relay protection circuit includes a current transformer on the neutral point side, a current transformer on the outgoing line side, and a differential current relay, wherein the current transformer on the neutral point side and the current transformer on the outgoing line side are respectively Including three-phase windings, each phase winding of the three-phase windings corresponds to a differential current relay, one end of each phase winding of the neutral point side current transformer is connected to the neutral point side of the generator, and the outgoing line side current One end of each phase winding of the transformer is connected to the outgoing line side of the generator, and the other end of each phase winding of the current transformer on the neutral point side is connected to the other end of each phase winding of the outgoing line current transformer respectively. Corresponding to the input terminal of the differential current relay.

The current transformer on the neutral point side is used to obtain the current on the neutral point side; the current transformer on the outgoing line side is used to obtain the current on the outgoing line side; And the operating current of the differential current relay to determine whether the generator has a fault within the protection range.

The generator relay protection circuit provided by this application is applied to the scenario where multiple generators are running in parallel in the data center, and the neutral point grounding method of multiple generators is single-point grounding through a small resistance. Both the neutral point side and the outgoing line side are connected with current transformers, so that it can be determined whether the generator has a fault within the protection range according to the neutral point side current, the outgoing line side current and the operating current of the differential current relay. Compared with the existing technology Compared with the overcurrent protection in the system, since it can be determined whether the generator has a fault within the protection range according to the neutral point side current, the outlet side current and the operating current of the differential current relay, for the generator that has a fault within the protection range The disconnection is performed, and the generators that do not have a fault within the protection range must not be operated. In this way, the faulty generator can be accurately determined and the faulty generator can be disconnected.

Furthermore, the generator relay protection circuit provided by this application can cut off the faulty generator without delay when it is determined that a fault occurs within the protection range of the generator. Compared with the overcurrent protection in the prior art, this The generator relay protection circuit provided by the application is sensitive to faults within the generator protection range, and can quickly determine the faulty generator.

In the first optional implementation manner of the second aspect, the operating current of the above-mentioned differential current relay satisfies:

I _dz ＞I _bpmax , and I _dz ≥K× _IN , where I _dz is the operating current of the differential current relay, I _bpmax is the maximum unbalanced current, K is the reliability factor, and I _N is the rated current of the generator.

In a second optional implementation of the second aspect, the above differential current relay is specifically used to determine the input current of the differential current relay according to the current on the neutral point side and the current on the outgoing line side; When the direction of the current is opposite to that of the outlet side current, and the value of the input current of the differential current relay is greater than or equal to the value of the operating current of the differential current relay, it is determined that the generator has a fault within the protection range; When the direction of the current is the same as that of the outlet side current, and the value of the input current of the differential current relay is less than the value of the operating current of the differential current relay, it is determined that the generator does not have a fault within the protection range.

In a third optional implementation manner of the second aspect, the fact that the generator does not have a fault within the protection range includes that the generator is running normally or the generator has a fault outside the protection range.

For descriptions of technical effects of various optional implementations of the second aspect, reference may be made to descriptions of technical effects of various optional implementations of the first aspect, and details are not repeated here.

Description of drawings

Fig. 1 is a schematic diagram of neutral point grounding of a generator provided by an embodiment of the present invention;

Fig. 2 is a schematic diagram of a generator relay protection circuit provided by an embodiment of the present invention;

Fig. 3 is a second schematic diagram of a generator relay protection circuit provided by an embodiment of the present invention;

Fig. 4 is a third schematic diagram of a generator relay protection circuit provided by an embodiment of the present invention;

Fig. 5 is a fourth schematic diagram of a generator relay protection circuit provided by an embodiment of the present invention;

Fig. 6 is a schematic diagram 5 of a generator relay protection circuit provided by an embodiment of the present invention;

Fig. 7 is a sixth schematic diagram of a generator relay protection circuit provided by an embodiment of the present invention;

Fig. 8 is a schematic diagram 1 of a generator relay protection method provided by an embodiment of the present invention;

Fig. 9 is a second schematic diagram of a generator relay protection method provided by an embodiment of the present invention;

Fig. 10 is a third schematic diagram of a generator relay protection method provided by an embodiment of the present invention;

Fig. 11 is a schematic diagram 4 of a generator relay protection method provided by an embodiment of the present invention;

Fig. 12 is a schematic diagram 5 of a generator relay protection method provided by an embodiment of the present invention;

Fig. 13 is a sixth schematic diagram of a generator relay protection method provided by an embodiment of the present invention;

Fig. 14 is a seventh schematic diagram of a generator relay protection method provided by an embodiment of the present invention.

Detailed ways

In the embodiments of the present invention, words such as "exemplary" or "for example" are used as examples, illustrations or illustrations. Any embodiment or design solution described as "exemplary" or "for example" in the embodiments of the present invention shall not be construed as being more preferred or more advantageous than other embodiments or design solutions. Rather, the use of words such as "exemplary" or "such as" is intended to present related concepts in a concrete manner.

In the description of the embodiments of the present invention, unless otherwise specified, "plurality" means two or more. For example, multiple processing units refer to two or more processing units; multiple systems refer to two or more systems.

First, some concepts involved in the generator relay protection method and circuit provided by the embodiment of the invention are explained.

Faults within the protection range: When the relay protection mechanism of the generator is differential protection, as shown in Figure 2, the outgoing line side and the neutral point side of the generator are respectively connected to a current transformer, and the outgoing line side current transformer and the neutral point The part between the side current transformers is called the protection range (area 1 is taken as an example in Figure 2), and when the equipment on the circuit between the outlet side current transformer and the neutral point side current transformer fails, the generator A fault within the protection range has occurred.

Faults outside the protection range: In the above Figure 2, the part outside the area 1 (including other equipment or distribution lines in the circuit of the generator, or other generators in the data center) is called outside the protection range, outside the protection range When a fault occurs, it is considered that the generator has a fault outside the protection range.

Based on the problems existing in the background technology, the embodiments of the present invention provide a generator relay protection method and circuit, which are applied to the scenario where multiple generators are running in parallel in a data center. The neutral point grounding mode of the multiple generators is For single-point grounding through a small resistance (that is, the neutral point grounding method described in (b) in Figure 1), for each generator, a differential protection mechanism is used (that is, the outgoing line side and the neutral point side of the generator are connected with current transformers), through the neutral point side current of the generator, the outlet side current of the generator and the operating current of the differential current relay, it can be determined whether the generator has a fault within the protection range, which can be more quickly and accurately Identify the failed generator.

The generator relay protection method and circuit provided in the embodiments of the present invention can be applied to medium-voltage diesel generators in data centers, and can also be applied to other generators such as medium-voltage gas generators, which are not specifically limited in the embodiments of the present invention. It should be noted that the neutral point grounding method of multiple medium-voltage diesel generators in the data center is single-point grounding through a small resistance. The following uses the medium-voltage diesel generators in the data center as an example to introduce in detail the methods provided by the embodiments of the present invention. Generator relay protection method and circuit.

The embodiment of the present invention provides a generator relay protection circuit, which can be applied to the scenario where multiple generators run in parallel in a data center. As shown in Figure 3, multiple generators running in parallel Taking a generator in the machine as an example, the generator relay protection circuit includes a current transformer 10 on the neutral point side, a current transformer 11 on the outgoing line side, and a differential current relay 12 (in Fig. 3, the differential current relay 12 Including 12a, 12b and 12c), wherein, the neutral point side current transformer 10 and the outgoing line side current transformer 11 respectively include three-phase windings, and each phase winding of the three-phase windings corresponds to a differential current relay (respectively 12a, 12b and 12c), one end of each phase winding of the neutral point side current transformer 10 is connected to the neutral point side of the generator, and one end of each phase winding of the outgoing line side current transformer 11 is connected to the outgoing line side of the generator , and the other end of each phase winding of the neutral point side current transformer 10 and the other end of each phase winding of the outlet side current transformer 11 are respectively connected to the input end of the corresponding differential current relay.

In FIG. 3 , the three-phase windings of the current transformer 10 on the neutral point side are respectively marked as A1 , B1 and C1 , and the three-phase windings of the current transformer 11 on the outlet side are respectively marked as A2 , B2 and C2 . Each phase winding of the three-phase winding corresponds to a differential current relay respectively, that is, winding A1 and winding A2 correspond to the differential current relay 12a, winding B1 and winding B2 correspond to the differential current relay 12b, and winding C1 and winding C2 correspond to the differential current relay 12c. Specifically, one end of winding A1 (denoted as p1 terminal) is connected to the neutral point side of the generator, and the other end of winding A1 (denoted as q1 terminal) is connected to input terminal x1 of differential current relay 12a. Similarly, winding B1 Terminal p1 of winding B1 is connected to the neutral point side of the generator, terminal q1 of winding B1 is connected to input terminal x2 of differential current relay 12b, terminal p1 of winding C1 is connected to the neutral point side of the generator, terminal q1 of winding C1 Connect to the input terminal x3 of the differential current relay 12c; one end of the winding A2 (denoted as the p2 terminal) is connected to the outlet side of the generator, and the other end of the winding A2 (denoted as the q2 terminal) is connected to the input terminal of the differential current relay 12a x1, similarly, the p2 terminal of winding B2 is connected to the outgoing line side of the generator, the q2 terminal of winding B2 is connected to the input terminal x2 of differential current relay 12b, the p2 terminal of winding C2 is connected to the outgoing line side of the generator, and the winding C2 The q2 terminal of the differential current relay 12c is connected to the input terminal x3 of the differential current relay 12c, and the connection relationship of each component is specifically referred to in FIG. 3 .

The above-mentioned current transformer 10 on the neutral point side is used to acquire the current on the neutral point side.

In the embodiment of the present invention, the current transformer on the neutral point side can convert the primary current on the neutral point side of the generator into a secondary current, wherein the primary current is greater than the secondary current. In the following embodiments, the current converted by the current transformer on the neutral point side (ie, the secondary current) is referred to as the neutral point side current.

It should be noted that since the current transformer on the neutral point side includes three-phase windings, the current on the neutral point side includes three-phase currents, the directions of the three-phase currents are the same, and the magnitudes of the three-phase currents can be the same or different.

The outgoing line side current transformer 11 is used to acquire the outgoing line side current.

In the embodiment of the present invention, the current transformer on the outlet side can convert the primary current on the outlet side of the generator into a secondary current, wherein the primary current is greater than the secondary current. In the following embodiments, the current converted by the current transformer on the outgoing line side (ie, the secondary current) is referred to as the outgoing line side current.

Similar to the above-mentioned current transformer on the neutral point side, since the current transformer on the outlet side also includes a three-phase winding, the current on the outlet side includes three-phase currents, the directions of the three-phase currents are the same, and the magnitudes of the three-phase currents can be the same or different.

The above-mentioned differential current relay 12 is used to determine whether the generator has a fault within the protection range according to the neutral point side current, the outgoing line side current and the operating current of the differential current relay.

Among them, the operating current of the differential current relay satisfies: I _dz > I _bpmax , and I _dz ≥ K× _IN , where I _dz is the operating current of the differential current relay, I _bpmax is the maximum unbalanced current, and K is the reliable Coefficient, I _N is the rated current of the generator.

Specifically, the above-mentioned _Idz may include _{Idz_a} , _{Idz_b} , and _{Idz_c} , and these three currents are the operating currents of the differential current relays 12a, 12b, and 12c respectively. Similarly, _Ibpmax may also include _{Ibpmax_a} , _{Ibpmax_b} , and I _{bpmax_c} , these three currents are respectively the maximum unbalanced currents corresponding to the differential current relays 12a, 12b, and 12c.

In the embodiment of the present invention, the operating current of the differential current relay is greater than the maximum unbalanced current, which can avoid the differential The current relay malfunctions, and the operating current of the differential current relay is greater than or equal to K times the rated current, which can prevent the differential current relay from malfunctioning when the current caused by the disconnection of the secondary current loop flows into the differential current relay.

Optionally, in the embodiment of the present invention, the value of the operating current of the differential current relay can be K× _Ibpmax , K is a reliability coefficient (for example, the value of K can be 1.3), and the operating current of the differential current relay can also be It is other values that meet actual usage requirements, and is not specifically limited in this embodiment of the present invention.

Optionally, the differential current relay 12 is specifically used to determine the input current of the differential current relay according to the current on the neutral point side and the current on the outgoing line side; the direction of the current on the neutral point side is opposite to the direction of the current on the outgoing line side, and When the value of the input current of the differential current relay is greater than or equal to the value of the action current of the differential current relay, it is determined that the generator has a fault within the protection range; the direction of the current at the neutral point side is the same as that of the outgoing line side current, and When the value of the input current of the differential current relay is smaller than the value of the operating current of the differential current relay, it is determined that the generator does not have a fault within the protection range.

It should be noted that, in the embodiment of the present invention, the above-mentioned three-phase windings correspond to three differential current relays, and the three differential current relays respectively The operating current determines whether the generator has a fault within the protection range, and then combines the determined results of the three differential current relays to determine whether the generator has a fault within the protection range.

Exemplarily, with reference to FIG. 3 , the three-phase currents included in the neutral point side current, the three-phase currents included in the outgoing line side current, and the differential current relays corresponding to each phase current are shown in Table 1 below.

Table 1

Neutral side current i ₁ Outgoing side current i ₂ Differential Current Relay i _1A i ₂ Differential current relay 12a i _1B i _2B Differential current relay 12b i _{1C i2C} Differential current relay 12c

In Table 1, the three-phase currents included in the neutral point side current are respectively i _1A , i _1B and i _1C , where the winding A1 of the current transformer 10 corresponds to i _1A , and the winding B1 of the current transformer 10 corresponds to i _1B , The winding C1 of the current transformer 10 corresponds to i _1C , and the three-phase currents included in the outlet side current are respectively i _2A , i _2B and i _2C , wherein, the winding A2 of the current transformer 11 corresponds to i _2A , and the winding B2 of the current transformer 11 Corresponding to i _2B , the winding C2 of the current transformer 11 corresponds to i _2C .

Exemplarily, taking i _1A and i _2A as an example, the differential current relay 12a can determine the input current i _Ja of the differential current relay 12a according to i _1A and i _2A , i _Ja =i _1A +i _2A , assuming the differential The value of the input current i _Ja of the current relay 12a is I _Ja , and the value of the operating current of the differential current relay 12a is I _{dz_a} , if the direction of i _1A is opposite to that of i _2A , and I _Ja ≥ I _{dz_a} , that is, differential The input current of the current relay 12a exceeds the operating current of the differential current relay 12a. At this time, the differential current relay 12a determines that a fault occurs within the protection range of the generator, and the relay switch of the differential current relay 12a is closed. If the direction of i _1A is the same as that of i _2A , and I _Ja < I _{dz_a} , that is, the input current of the differential current relay 12a does not exceed the operating current of the differential current relay 12a, then the differential current relay 12a determines that the generator If no fault within the protection range occurs, the state of the relay switch of the differential current relay 12a remains unchanged (the state of the relay switch of the differential current relay 12a remains open).

As shown in Figure 4, in an optional implementation method, the direction of i _1A is the direction of flowing from the current transformer on the neutral point side to the generator, and the direction of i _2A is the direction of flowing from the current transformer on the outlet side to the generator , that is, the direction of i _1A is opposite to that of i _2A , then for the reference point M in Fig. 4, according to Kirchhoff's principle, it can be known that the value of the input current i _Ja of the differential current relay 12a is:

I _Ja ＝ I _1A +I _2A

Wherein, I _Ja is the value of the input current i _Ja of the differential current relay 12a, I _1A is the value of i _1A , and I _2A is the value of i _2A .

As shown in Figure 5, in another optional implementation, the direction of i _1A is the direction of flowing from the current transformer on the neutral point side to the generator, and the direction of i _2A is the direction of flowing from the generator to the current transformer on the outlet side , that is, the direction of i _1A is the same as that of i _2A , then for the reference point M in Figure 5, according to Kirchhoff's principle, it can be known that the value of the input current i _Ja of the differential current relay 12a is:

I _Ja ＝ I _1A -I _2A

It should be noted that, in the embodiment of the present invention, when the characteristics of the current transformer on the neutral point side and the current transformer on the outgoing line side are the same, and I _1A is equal to I _2A , then the value I _Ja of the current flowing into the differential current relay 12a is 0, it is determined that there is no fault within the protection range of the generator; when the characteristics of the current transformer on the neutral point side and the current transformer on the outlet side are the same, I _1A and I _2A may not be equal, and there is a current flowing through the differential current at this time The relay 12a, which flows through the differential current relay 12a is called an unbalanced current, because the value of the operating current of the differential current relay 12a is greater than the maximum unbalanced current corresponding to the differential current relay 12a, that is, I _{dz_a} > I _{bpmax_a} , then it is determined There is no fault within the protection range of the generator.

Optionally, in this embodiment of the present invention, the fact that the generator does not have a fault within the protection range includes that the generator is running normally or that the generator has a fault outside the protection range.

In the embodiment of the present invention, the differential current relay 12b and the differential current relay 12c determine whether the generator has a fault within the protection range. For the specific differential current relay 12b and differential current relay 12c to determine whether the generator has a fault within the protection range, for details, please refer to the above-mentioned embodiment for the differential current relay 12a to determine whether the generator has a fault within the protection range description, which will not be repeated here.

Optionally, in combination with FIG. 3 , as shown in FIG. 6 , the generator relay protection circuit provided by the embodiment of the present invention further includes a signal relay 13 , a magnetic trip switch 14 , a TA disconnection relay 15 and a disconnection signal relay 16 , TA is the electrical symbol of the current relay. Wherein, the output end of differential current relay 12a, 12b and 12c is connected with the input end of signal relay 13 respectively; The output end of signal relay 13 is connected with the input end of tripping magnetic switch 14; The output terminals of the TA disconnection relay 15 are respectively connected to the input terminal of the TA disconnection relay 15, the output terminal of the TA disconnection relay 15 is grounded, and the outlet of the TA disconnection relay 15 is connected to the input terminal of the disconnection signal relay 16, and the neutral point side current mutual inductance The neutral point of the transformer and the neutral point of the current transformer on the outlet side are grounded.

The above-mentioned signal relay 13 is used to close the relay switch of at least one differential current relay in the differential current relays 12a, 12b, 12c (that is, the value of the input current of at least one differential current relay is greater than or equal to the corresponding differential current relay) value of the operating current of the current relay), a fault signal is output. Specifically, the closing of the relay switch of at least one of the differential current relays 12a, 12b, 12c will trigger the closing of the relay switch of the signal relay 13 to output a fault signal.

The above magnetic switch 14 is used to close the magnetic switch of the signal relay 13 when the relay switch of the signal relay 13 is closed to trigger the removal of the generator that has a fault within the protection range, so as to avoid damage to other equipment or distribution equipment in the generator system of the data center. The impact caused by the electric line causes a secondary fault.

It should be noted that, in the embodiment of the present invention, when the values of the input currents of the above three differential current relays 12a, 12b, and 12c are all smaller than the values of the operating currents of the corresponding differential current relays, then It is determined that the generator has a fault within the protection range, the states of the relay switches of the differential current relays 12a, 12b, and 12c remain unchanged (still open), and the generator continues to run.

The above-mentioned TA disconnection relay 15 is used to judge whether the secondary current circuit of the current transformer is disconnected, and the value of the input current of the relay 15 is greater than or equal to the value of the operating current of the TA disconnection relay 15 to determine whether the secondary current circuit is disconnected. Disconnection: The value of the input current of the TA disconnection relay 15 is smaller than the value of the operating current of the TA disconnection relay 15, and it is determined that the secondary current circuit does not have a disconnection.

The disconnection signal relay 16 is used to close the relay switch of the TA disconnection relay 15 and output a disconnection signal when the relay switch of the disconnection relay 15 is closed.

It should be noted that, in the embodiment of the present invention, multiple generators in the data center run in parallel, and the neutral point grounding method of multiple generators is single-point grounding through a small resistance, and the grounding mode of multi-point grounding with the generators Compared with the grounding method of single-point contact, the fault current when the generator fails is relatively small, which can reduce the impact on other equipment or distribution lines in the generator system to a certain extent.

Taking a generator as an example, if the generator is a grounded generator among multiple generators running in parallel, the neutral point of the generator is grounded through a small resistor, as shown in Figure 6, the generator’s The neutral point is grounded through a small resistor R; if the generator is an ungrounded generator among multiple parallel generators, as shown in Figure 7, the neutral point of the generator is not grounded.

Furthermore, when the above-mentioned electromechanical protection circuit is used for multiple generators in the data center, on the one hand, when a fault occurs within the protection range of the generator that is grounded through a small resistance among the multiple generators, the input current of the differential current relay is less than The withstand current of the neutral point grounding resistance cabinet, so when a fault occurs within the protection range of the generator grounded by a small resistance, it will not cause impact on other equipment or distribution lines in the generator system; on the other hand, many When an ungrounded generator fails within the protection range, the input current of the differential current relay is less than the withstand current of the neutral point grounding resistance cabinet, so when an ungrounded generator fails within the protection range , and will not cause impact on other equipment or distribution lines in the generator system.

The generator relay protection circuit provided by the embodiment of the present invention is applied to the scenario where multiple generators are running in parallel in the data center, and the neutral point grounding mode of multiple generators is single-point grounding through a small resistance, and the power generation Both the neutral point side and the outgoing line side of the generator are connected with current transformers, so that it can be determined whether the generator has a fault within the protection range according to the current on the neutral point side, the outgoing line side current and the operating current of the differential current relay. Compared with the overcurrent protection in the prior art, since it can be determined whether the generator has a fault within the protection range according to the neutral point side current, the outlet side current and the operating current of the differential current relay, for the fault within the protection range The generator is cut off, and the generator that does not have a fault within the protection range is reliably inactive (that is, the generator continues to run). In this way, the faulty generator can be accurately determined and the faulty generator can be cut off.

Furthermore, the generator relay protection circuit provided by the embodiment of the present invention can cut off the faulty generator without delay when it is determined that the generator has a fault within the protection range, compared with the overcurrent protection in the prior art , the generator relay protection circuit provided by the embodiment of the present invention is sensitive to the fault within the generator protection range, and can quickly determine the faulty generator.

The generator relay protection method provided by the embodiment of the present invention can be applied to the scenario where multiple generators are running in parallel in the data center, and the neutral point grounding method of multiple generators is single-point grounding through a small resistance, so as to Taking one generator among multiple generators as an example, the execution subject of the relay protection method of the generator may be the relay control module in the generator relay protection circuit, combined with Fig. 3, as shown in Fig. 8, the Methods may include S101-S103:

S101. Obtain the neutral point side current of the generator.

The current on the neutral point side is the current transformed by the current transformer on the neutral point side of the generator.

S102. Obtain the current on the outlet side of the generator.

The outgoing line current is the current transformed by the current transformer on the outgoing line side of the generator.

S103. Determine whether the generator has a fault within the protection range according to the neutral point side current, the outgoing line side current and the operating current of the differential current relay.

For the description of the relevant content of S101-S103, please refer to the above description of the relevant content in the relay protection circuit of the generator as shown in FIG.

Optionally, in combination with FIG. 8, as shown in FIG. 9, the above S103 can be specifically implemented through S1031-S1032:

S1031. Determine the input current of the differential current relay according to the neutral point side current and the outgoing line side current.

S1032. According to the value of the input current of the differential current relay and the value of the operating current of the differential current relay, determine whether the generator has a fault within the protection range.

For the related description of S1031-S1032, please refer to the specific description of the differential current relay 12 (including the differential current relays 12a, 12b and 12c) in the generator relay protection circuit above, which will not be repeated here.

Optionally, in this embodiment of the present invention, the above S1032 may specifically include S1032a or S1032b:

Combined with Figure 9, as shown in Figure 10, after determining the input current of the differential current relay according to the neutral point side current and the outgoing line side current, you can execute:

S1032a. When the direction of the neutral point side current is opposite to that of the outgoing line side current, and the value of the input current of the differential current relay is greater than or equal to the value of the operating current of the differential current relay, it is determined that the generator has a fault within the protection range .

Combined with Figure 9, as shown in Figure 11, after determining the input current of the differential current relay according to the neutral point side current and the outlet side current, you can execute:

S1032b. When the direction of the neutral point side current is the same as that of the outgoing line side current, and the value of the input current of the differential current relay is less than the value of the operating current of the differential current relay, it is determined that the generator does not have a fault within the protection range.

In the embodiment of the present invention, referring to Fig. 3, the neutral point side current and the outgoing line side current respectively include three-phase currents, and each phase current of the three-phase currents corresponds to a differential current relay, as shown in Fig. 12 in conjunction with Fig. 8 , the above S103 can be specifically realized through S1033-S1034:

S1033. Determine the input current of each differential current relay according to the current of each phase at the neutral point side and the current of each phase at the outgoing line side.

S1034. According to the values of the input currents of the three differential current relays and the respective operating current values of the three differential current relays, determine whether the generator has a fault within the protection range.

Optionally, in this embodiment of the present invention, the above S1034 may specifically include S1034a or S1034b:

Combined with Figure 12, as shown in Figure 13, after determining the input current of the differential current relay according to the neutral point side current and the outgoing line side current, you can execute:

S1034a. The direction of the neutral point side current is opposite to that of the outgoing line side current, and the value of the input current of at least one of the three differential current relays corresponding to the three-phase current is greater than or equal to the differential current relay When the value of the operating current is determined, it is determined that the generator has a fault within the protection range;

Combined with Figure 12, as shown in Figure 14, after determining the input current of the differential current relay based on the neutral point side current and the outgoing line side current, you can execute:

S1034b. When the direction of the neutral point side current is opposite to that of the outgoing line side current, and the input current values of the three differential current relays corresponding to the three-phase current are all less than the operating current value of the differential current relay, determine the power generation There is no failure within the protection range of the machine.

In the embodiment of the present invention, the failure of the above-mentioned generator within the protection range includes normal operation of the generator or failure of the generator outside the protection range.

It should be noted that the generator relay protection method provided by the embodiment of the present invention can be applied to the generator relay protection circuit described in the above embodiment. For the detailed description of each step of the generator relay protection method, refer to the above The description of the related content of the generator relay protection circuit in the embodiment will not be repeated here.

The generator relay protection method provided by the embodiment of the present invention is applied to the scene where multiple generators are running in parallel in the data center, and the neutral point grounding method of multiple generators is single-point grounding through a small resistance, because it can According to the neutral point side current, the outlet side current and the action current of the differential current relay, determine whether the generator has a fault within the protection range, and cut off the generator that has a fault within the protection range. A failed generator is surely not operated, and thus, it is possible to accurately identify a failed generator and cut off the failed generator.

Furthermore, the generator relay protection method provided by the embodiment of the present invention can cut off the faulty generator without delay when it is determined that a fault occurs within the protection range of the generator, compared with the overcurrent protection in the prior art , the generator relay protection circuit provided by the embodiment of the present invention is sensitive to the fault within the generator protection range, and can quickly determine the faulty generator.

The above is only a specific implementation of the application, but the protection scope of the application is not limited thereto, and any changes or replacements within the technical scope disclosed in the application should be covered within the protection scope of the application . Therefore, the protection scope of the present application should be determined by the protection scope of the claims.

Claims (9)

1. A generator relay protection method, characterized in that it is applied to the scenario where multiple generators are running in parallel in a data center, and the neutral point grounding mode of the multiple generators is single-point grounding through a small resistance , the method includes: Obtaining the current on the neutral point side of the generator, where the current on the neutral point side is the current converted by the current transformer on the neutral point side of the generator; Obtain the current on the outlet side of the generator, where the current on the outlet side is the current converted by the current transformer on the outlet side of the generator; According to the neutral point side current, the outgoing line side current and the operating current of the differential current relay, it is determined whether the generator has a fault within the protection range. 2. The method of claim 1, wherein, The operating current of the differential current relay satisfies: I _dz > I _bpmax , and I _dz ≥ K× _IN , wherein, I _dz is the operating current of the differential current relay, I _bpmax is the maximum unbalanced current, K is the reliability factor, and _IN is the rated current of the generator. 3. The method according to claim 1 or 2, characterized in that, according to the neutral point side current, the outgoing line side current and the operating current of the differential current relay, it is determined whether the generator is protected A wide range of faults, including: determining the input current of the differential current relay according to the neutral point side current and the outgoing line side current; When the direction of the neutral point side current is opposite to the direction of the outlet side current, and the value of the input current of the differential current relay is greater than or equal to the value of the operating current of the differential current relay, it is determined that the The generator has a fault within the protection range; When the direction of the neutral point side current is the same as the direction of the outgoing line side current, and the value of the input current of the differential current relay is smaller than the value of the operating current of the differential current relay, it is determined that the generator No faults within the protection range have occurred. 4. The method according to any one of claims 1 to 3, wherein the neutral point side current and the outgoing line side current respectively comprise three-phase currents, and each phase current of the three-phase currents corresponds to A differential current relay, which determines whether the generator has a fault within the protection range according to the neutral point side current, the outlet side current and the operating current of the differential current relay, including: determining the input current of each differential current relay according to each phase current on the neutral point side and each phase current on the outgoing line side; The direction of the neutral point side current is opposite to the direction of the outlet side current, and the value of the input current of at least one of the three differential current relays corresponding to the three-phase current is greater than or equal to When the value of the operating current of the differential current relay is determined, it is determined that the generator has a fault within the protection range; The direction of the neutral point side current is opposite to the direction of the outlet side current, and the values of the input currents of the three differential current relays corresponding to the three-phase currents are all smaller than the operating current values of the differential current relays , it is determined that the generator does not have a fault within the protection range. 5. The method according to claim 3 or 4, characterized in that, The fact that the generator does not have a fault within the protection range includes that the generator is running normally or that the generator has a fault outside the protection range. 6. A relay protection circuit for a generator, characterized in that it is applied to the scenario where multiple generators are running in parallel in a data center, and the neutral point grounding method of the multiple generators is single-point grounding through a small resistance , the generator relay protection circuit includes a neutral point side current transformer, an outgoing line side current transformer, and a differential current relay, wherein the neutral point side current transformer and the outgoing line side current transformer are respectively It includes a three-phase winding, each phase winding of the three-phase winding corresponds to a differential current relay, and one end of each phase winding of the neutral point side current transformer is connected to the neutral point side of the generator, One end of each phase winding of the outgoing line current transformer is connected to the outgoing line side of the generator, and the other end of each phase winding of the neutral point side current transformer is connected to the outgoing line side current transformer. The other end of each phase winding is respectively connected to the input end of the corresponding differential current relay; The current transformer on the neutral point side is used to obtain the current on the neutral point side; The outgoing line side current transformer is used to obtain the outgoing line side current; The differential current relay is used to determine whether the generator has a fault within the protection range according to the neutral point side current, the outgoing line side current and the operating current of the differential current relay. 7. The circuit of claim 6, wherein The operating current of the differential current relay satisfies: I _dz > I _bpmax , and I _dz ≥ K× _IN , wherein, I _dz is the operating current of the differential current relay, I _bpmax is the maximum unbalanced current, K is the reliability factor, and _IN is the rated current of the generator. 8. The circuit according to claim 6 or 7, characterized in that, The differential current relay is specifically used to determine the input current of the differential current relay according to the neutral point side current and the outgoing line side current; the direction of the neutral point side current and the outgoing line side current direction is opposite, and the value of the input current of the differential current relay is greater than or equal to the value of the operating current of the differential current relay, it is determined that the generator has a fault within the protection range; at the neutral point When the direction of the side current is the same as that of the outlet side current, and the value of the input current of the differential current relay is less than the value of the operating current of the differential current relay, it is determined that the generator is not within the protection range failure. 9. The circuit of claim 8, wherein The fact that the generator does not have a fault within the protection range includes that the generator is running normally or that the generator has a fault outside the protection range.