JPH10164749A - Protective device for dynamo-electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect winding internal abnormality of a dynamo-electric machine before an actual accident occurs, and detect abnormality of overvoltage, overcurrent or the like. SOLUTION: This device is provided with voltage detectors VU1 to VU6 , VV1 to VV6 and VW1 to VW6 at connection parts of respective phases and respective poles of stator winding crossover of a generator, and detected voltage by respective voltage detectors is time-integrated by magnetic flux calculating part BU1 to BU6 , BV1 to BV6 and BW1 to BW6 to obtain magnetic flux amount ϕU1 to ϕU6 , ϕV1 to ϕV6 , and ϕW1 to ϕW6 . Magnetic flux addition parts 101, 102 and 103 of the respective phases add the magnetic flux amount for respective phases of obtain gross amount magnetic flux ΣϕU, ΣϕV, and ΣϕW. An abnormality judging part 104 judges abnormality from the gross amount magnetic flux ΣϕU, ΣϕV, and ΣϕW, and if judged as abnormal, it outputs a trip command T or generates warning.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a protection device for a rotating electrical machine, and more particularly to an apparatus for protecting a rotating electrical machine by detecting an accident of the rotating electrical machine accurately and quickly. More specifically, in the present invention, the state of each coil of the rotary electric machine is detected accurately and quickly by monitoring the amount of magnetic flux of each coil to detect an accident of the rotary electric machine. It is.

[0002]

2. Description of the Related Art In order to protect a rotating electric machine (a generator or an electric motor) from an accident, a protecting device is attached to the rotating electric machine. Here, a general example of the types of accidents and a method of protecting against accidents will be described using a generator as an example.

[0003] Examples of the accident include short-circuits between layers, short-circuits between layers, overvoltages, overcurrents, etc. occurring in the stator windings of the generator. Among such accidents, if, for example, an inter-phase short-circuit or interlayer short-circuit occurs, the generator coil may be burnt, and the accident may be spread to a system accident. The overvoltage may be caused when the load is cut off due to a transmission line failure, when a resonance voltage abnormality occurs due to an unbalanced accident such as a one-wire ground fault or a two-wire short circuit occurring in the system, when an AVR fails, This occurs when a self-excitation phenomenon occurs. Further, an overcurrent is caused by a short circuit accident or the like.

[0004] An interlayer short-circuit is a short-circuit due to insulation breakdown between conductors and deterioration of insulation as shown by the mark x in FIG.
Also, in FIG. 3, 01 is a wedge, 02a, 02b, 02
c and 02d are coils.

As a method for protecting against the above-mentioned accidents, a method is employed in which each accident is detected by a relay and a circuit breaker is tripped when an accident occurs. In general, a ratio differential relay is used for detecting an inter-phase short-circuit fault or an interlayer short-circuit fault, an over-voltage relay is used for detecting an overvoltage, and an overcurrent relay is used for detecting an overcurrent.

Next, a specific example of a conventional protection device for protecting a generator will be described with reference to FIG. The protection device shown in FIG. 4 protects the short-circuit accident, overexcitation, and overload of the generator AG. That is, when an overcurrent occurs due to a short circuit accident or the like, the overcurrent relay 51 detects the overcurrent, outputs a trip command to the circuit breaker 52, and trips the circuit breaker 52. When an overvoltage occurs due to an overload or the like, the overvoltage relay 59 detects the overvoltage, outputs a trip command to the circuit breaker 52, and trips the circuit breaker 52. Further, when the voltage exceeds the rated voltage and becomes a specified voltage due to overexcitation or the like, the specified voltage relay 84 detects the specified voltage, outputs a trip command to the circuit breaker 52, and trips the circuit breaker 52.

In FIG. 4, CT is a current transformer, PT
Is an instrument transformer, W is a wattmeter, WH is a watt hour meter, V is a voltmeter, and A is an ammeter. In the apparatus shown in FIG. 4, the state of the generator AG is also remotely monitored by the remote monitoring apparatus 1.

[0008]

SUMMARY OF THE INVENTION In a conventional protection device,
As shown in FIG. 4, it is possible to protect the windings of the rotating electric machine (generator) to a certain extent against overcurrent and overvoltage caused by accidents such as three-phase short-circuit, one-line ground fault, and short-circuit between lines. is there. However, after the accident actually occurred, the accident was detected by a relay, and then the circuit breaker was tripped.
There is a time lag between the occurrence of the accident and tripping of the circuit breaker, and there is still room for improvement in terms of quick protection.

Further, although not shown in the example of FIG. 4, phase-to-phase short-circuits and interlayer short-circuits inside the windings can be generally detected by a ratio differential relay. There was still room for improvement in terms of protection. In addition, it was not possible to detect the degree of progress of the abnormality before a phase-to-phase short-circuit fault or an interlayer short-circuit fault inside the winding actually occurred.

In view of the above prior art, the present invention can accurately and promptly detect an accident of a rotating electrical machine to protect the rotating electrical machine and, even though the actual accident has not occurred, the abnormality (insulation) It is an object of the present invention to provide a protection device for a rotating electrical machine that can detect the degree of progress of an abnormality in advance (before an actual accident occurs) when deterioration or the like is in progress.

[0011]

SUMMARY OF THE INVENTION The present invention, which solves the above-mentioned problems, comprises a voltage detector provided at a connecting portion of a connecting wire of each pole of each phase of a stator winding of a rotary electric machine; A magnetic flux calculation unit that is individually connected to the voltage detector and calculates a magnetic flux amount that is a vector amount by time-integrating the voltage detected by the voltage detector, and a magnetic flux amount calculated by each magnetic flux calculation unit. Based on the value of the total magnetic flux amount obtained by the magnetic flux adding unit of each phase to obtain the total magnetic flux amount of each phase by adding separately for each phase, And a determination unit for determining abnormality.

Further, in the present invention, the abnormality determination unit may determine that the mutual values of the total magnetic flux amounts are not equal within a predetermined range, and that the values of the total magnetic flux amounts are within a predetermined range. In this case, when it is not equal to a preset initial total magnetic flux amount, it is determined that an abnormality is present.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a block diagram showing a protection device for a rotary electric machine according to an embodiment of the present invention, and FIG. 2 is a layout diagram showing a mounting state of a U-phase voltage detector of the protection device. The protection device according to the present embodiment is applied to a generator having a six-pole stator winding.

As shown in FIG. 1, according to the present embodiment.
In the protection device, the U-phase voltage detector V_u1~ V_u6For V phase
Voltage detector V_v1~ V_v6, V-phase voltage detector V_w1~ V
_w6Is the crossover of each pole of each phase of the stator winding (6 poles) of the generator.
It is connected to the joint. In other words, U-phase voltage detection
Vessel V_u1~ V_u6Is one of the U-phase crossovers as shown in FIG.
It is connected to the bridge. Although illustration is omitted, for V phase
Voltage detector V_v1~ V _v6And V-phase voltage detector V_w1~
V_w6Similarly, the connecting portion of the V-phase connecting wire and the connecting portion of the W-phase
It is connected to the connecting part of the stub.

U-phase voltage detectors V _{u1 to} V _u6 , V-phase voltage detectors V _{v1 to} V _v6 , W-phase voltage detectors V _{w1 to} V _w6
, The U-phase magnetic flux calculation units B _u1 to
B _u6 , V-phase magnetic flux calculation units B _{v1 to} B _v6 , and W-phase magnetic flux calculation units B _{w1 to} B _w6 are connected.

The magnetic flux calculation unit B _u1 .about.B _u6 for U-phase, by integrating the voltage detected by the voltage detector V _u1 ~V _u6 for U-phase time, calculates the amount of magnetic flux phi _u1 to [phi] _u6 . In this case, the reference vector of the magnetic flux phi _u1, calculates the amount of magnetic flux phi _u2 to [phi] _u6 having a phase and magnitude of a vector quantity.

Similarly, the magnetic flux calculation units B _{v1 to} B _v6 for the V phase are
The magnetic flux amounts φ _{v1 to} φ _v6 are calculated by integrating the voltages detected by the V-phase voltage detectors V _{v1 to} V _v6 with time. In this case, using the magnetic flux amount φ _v1 as a reference vector, the magnetic flux amounts φ _{v2 to} φ _v6 having the phase and magnitude as the vector amount are calculated.

Similarly, the magnetic flux calculation unit B for the W phase_w1~ B
_w6Is the voltage detector V for the W phase_w1~ V _w6The voltage detected at
By integrating over time, the amount of magnetic flux φ_w1~ Φ_w6Calculate
You. In this case, the amount of magnetic flux φ_w1With reference vector
Magnetic flux amount φ with phase and magnitude as vector amount_w2~
φ_w6Is calculated.

The flux addition section 101 for the U-phase, the amount of magnetic flux phi _u1 to [phi] calculated by the magnetic flux calculation unit B _u1 .about.B _u6 for U-phase
_u6 is added as a vector to determine the total magnetic flux amount Δφ _u of the U phase.

Similarly, the magnetic flux adding section 102 for the V-phase
Magnetic flux amount φ _v1 calculated by phase magnetic flux calculation units B _{v1 to} B _v6
Φφ _v6 is added in a vector manner to obtain the total magnetic flux amount of the V phase Σφ
_{Find v} .

Similarly, the magnetic flux adding section 103 for the W phase
Is the magnetic flux calculator B for the W phase_w1~ B_w6Magnetic flux calculated by
Quantity φ_w1~ Φ_w6Is added in a vector, and the total magnetic flux of W phase
Quantity Σφ _wAsk for.

When the abnormality judging unit 104 judges that an abnormality has occurred by a judgment method (first and second judgment methods) described later, it outputs a trip command T to trip the circuit breaker. , An alarm is issued. On the other hand, the trip command T and the alarm are not output in a normal state.

Here, a first determination method and a second determination method in the abnormality determination unit 104 will be described.

In the first determination method, the total magnetic flux amount of the U phase Σφ
_u , the total magnetic flux of the V phase Σφ _v, and the total magnetic flux of the W phase Σφ _w
Are determined to be equal within a predetermined range.
That is, it is determined whether the following equations (1) to (3) hold. Σφ _v ≒ Σφ _w (1) Σφ _u ≒ Σφ _v (2) Σφ _w ≒ Σφ _u (3) If the above equations (1) to (3) are satisfied, it is determined that the condition is normal. judge.

When it is determined in the first determination method that the state is not normal, a second determination method is performed. In the second determination method, the initial total magnetic flux amounts Σφ _ui , Σφ set for each phase are set.
_vi, and Σφ _wi, each phase the total amount of magnetic flux Σφ _u, Σφ _v, and the Σφ _w, determines whether or not the equivalent within a certain range set in advance.
That is, it is determined whether the following equations (4) to (6) hold. Uφ _u ≒ Σφ _ui・ ・ ・ (4) Σφ _v ≒ Σφ _vi・ ・ ・ (5) Σφ _w ≒ Σφ _wi・ ・ ・ (6)

Even if the above equations (1) to (3) do not hold,
If the above equations (4) to (6) are satisfied, it is determined that the state is normal.

If the above equations (1) to (3) do not hold, and if the above equations (4) to (6) do not hold, it is determined to be abnormal.

The initial set total magnetic flux Σφ _ui , Σφ _vi ,
Σφ _wi refers to the total amount of magnetic flux of each phase when the rotating electrical machine is operating at the rated load.

According to this protection device, even if an inter-phase short-circuit or interlayer short-circuit has not yet occurred inside the winding of the generator, if the inter-coil insulation breakdown or insulation deterioration has progressed to some extent, such insulation breakdown will occur. Etc. can be detected in advance (before an accident actually occurs). This is because if a certain degree of insulation deterioration or the like (insulation deterioration or the like that does not cause an accident) occurs, the state of magnetic flux at each pole of each phase of the winding deviates from the normal state. You can do it. Therefore, it is possible to prevent a serious accident such as an inter-phase short-circuit accident or an interlayer short-circuit accident from occurring.
Further, it is possible to prevent the occurrence of such an abnormality before the insulation deterioration of the coil or the like spreads to another coil.

Further, according to the present protection device, it is possible to detect overvoltage and overcurrent caused by line-to-line short-circuit, single-line ground fault, three-phase short-circuit, and the like. This means that if an overvoltage or overcurrent occurs,
Since the state of the magnetic flux at each pole of each phase of the winding deviates from the normal state, it can be determined that an abnormality has occurred. In this case, since the step of abnormality detection by the relay is not performed, abnormality detection can be performed quickly by that much, and stress on the winding due to overvoltage or overcurrent can be higher than that of the conventional technology that uses a relay to detect an accident. Can be reduced.

Further, in the present protection device, since the determination is performed in two steps by the first determination method and the second determination method,
Even if imbalance of total magnetic flux due to load imbalance occurs,
It can be distinguished from the imbalance of the total magnetic flux caused by the accident, and the judgment accuracy is improved. That is, when the imbalance of the total magnetic flux amount due to the load imbalance occurs, the first determination method of the equations (1) to (3) may not be satisfied.
Expressions (4) to (6), which are the second determination method, are satisfied, and it can be accurately determined that no accident has occurred. Note that overvoltage and overcurrent can be accurately determined only by the first determination method.

[0033]

According to the present invention, the abnormality is determined on the basis of the amount of magnetic flux, and the step of determining the abnormality by the relay is not required. Therefore, compared to the prior art using the relay,
Since the abnormality can be detected at an earlier timing, the rotating electric machine (such as a generator) can be protected accurately and quickly.

According to the present invention, abnormalities inside windings of a rotating electrical machine (interphase insulation deterioration and interlayer insulation deterioration) are detected at an early stage before an actual accident (interphase short-circuit accident or interlayer short-circuit accident) occurs. Can be. Therefore, it is possible to prevent a serious accident such as an inter-phase short-circuit accident or an interlayer short-circuit accident from occurring, and to protect the windings of the rotating electric machine before the inter-phase insulation deterioration or the like or the inter-layer insulation deterioration spreads to other coils.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a protection device for a rotating electrical machine according to an embodiment of the present invention.

FIG. 2 is a layout diagram showing a mounting state of a U-phase voltage detector in the protection device of the embodiment.

FIG. 3 is an explanatory diagram illustrating an interlayer short circuit accident.

FIG. 4 is a circuit diagram showing a protection device for a rotating electrical machine according to a conventional technique.

[Explanation of symbols]

1 remote monitor device 51 the overcurrent relay 59 overvoltage relay 84 defined voltage relay _{V u1 ~V u6, V v1 ~V} v6, V w1 ~V w6 voltage detector _{B u1 ~B u6, B v1 ~B} v6, B w1 ~ B _w6 magnetic flux calculation unit 101, 102, 103 Magnetic flux calculation unit 104 Abnormality determination unit

Claims (2)

[Claims] 1. A voltage detector provided at a connecting portion of a crossover wire of each pole of each phase of a stator winding of a rotary electric machine, and each of the voltage detectors is individually connected to each of the voltage detectors. A magnetic flux calculating unit that calculates a magnetic flux amount as a vector amount by time-integrating the voltage detected in the step; and a magnetic flux amount calculated by each magnetic flux calculating unit that is separately added for each phase and added to each phase. A magnetic flux adding unit for each phase for obtaining the amount of magnetic flux, and an abnormality determining unit for determining an abnormality based on the value of the total magnetic flux amount obtained by the magnetic flux adding unit for each phase. Protective device for rotating electrical machinery. 2. The abnormality determination unit according to claim 1, wherein mutual values of the total magnetic flux amounts are not equal within a predetermined range, and the values of the total magnetic flux amounts are within a predetermined range. 2. The protection device for a rotating electrical machine according to claim 1, wherein when it is not equal to a preset initial total magnetic flux amount, it is determined to be abnormal.