KR100905086B1 - Apparatus and controlling method for preventing mal-operation of sudden pressure relay system for transformer - Google Patents

Abstract

The present invention relates to an apparatus for preventing a malfunction of an impact pressure relay and a control method thereof. The present invention is to determine whether the operation of the over-current relay (OCR) or ground over-current relay (OCGR) for detecting the failure of the transformer external line, the impact pressure relay (SPR) for detecting the internal failure of the transformer and the operation sequence of the shock pressure relay If the impact pressure relay operates later than an overcurrent relay or a ground fault overcurrent relay, but the internal shock pressure of the shock pressure relay disappears within a predetermined time, the shock pressure relay is determined according to the determination result. It provides a configuration to control the trip signal by the non-occurrence. According to the present invention as described above, there is an advantage that the impact pressure relay for a transformer is prevented from malfunctioning due to an external fault current.

Shock pressure relay, overcurrent relay, trip signal, transformer

Description

Malfunction of transformer shock pressure relay and control method thereof {APPARATUS AND CONTROLLING METHOD FOR PREVENTING MAL-OPERATION OF SUDDEN PRESSURE RELAY SYSTEM FOR TRANSFORMER}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shock pressure relay (SPR) used in a transformer, and in particular, to prevent a malfunction of the shock pressure relay against a failure current of an external transformer and a method of preventing a malfunction of the shock pressure relay for a transformer and a control method thereof. It is about.

When an insulation failure with an arc occurs inside the transformer, gas generated by carbonization of the insulation and decomposition of the insulation oil is generated, and the internal pressure of the transformer rapidly increases. The pressure rise leads to a transformer failure. Therefore, a shock pressure relay is installed inside the transformer to detect this abnormal pressure rise and to disconnect the transformer from the track.

The shock pressure relay is installed inside the transformer and has been proposed to prevent a malfunction of the shock pressure relay system for protecting the transformer for blocking the transformer from the line according to the operation of the shock pressure relay.

For example, in Korean Patent Registration No. 10-0479692, a technique for preventing a shock pressure relay from malfunctioning due to an external accident of a transformer is applied.

Figure 1 is a circuit diagram of a conventional shock pressure relay system for transformer protection.

Referring briefly to FIG. 1, the current sensing unit 8 and the voltage sensing unit 9 sense current and voltage values of respective phases of the transformer secondary line 3 to detect the directional overcurrent relay 10. Enter

The directional overcurrent relay 10 collects / stores the current value and the voltage value by data, and determines the failure state, the type and the direction of the failure by referring to the switching unit 11 installed in the control signal output line 7. Operate.

Accordingly, if a failure of the track side is detected, the controller (not shown) generates a control signal for opening the contact of the switching unit 11 in order to prevent a malfunction of the impact pressure relay (6).

When the contact point of the switching unit 11 is opened by the control signal, the shock pressure relay 6 malfunctions due to an external failure of the transformer 1, that is, a failure of the line side, causing the primary side line 2 and the secondary side line to malfunction. Even when a control signal for turning off the circuit breakers 4 and 5 provided at the output is interrupted, the circuit breakers 4 and 5 do not operate because the output control signal is interrupted by the switching section 11 with the contact open. .

That is, the configuration of FIG. 1 prevents malfunction of the impact pressure relay 6 by blocking an output signal of the impact pressure relay 6 when a failure occurs in the external line of the transformer 1 by measuring current and voltage of the line side. have.

However, the above-described prior art has the following problems.

In the conventional malfunction prevention device, the signal output from the impact pressure relay 6 is cut off regardless of the operating state of the impact pressure relay 6. In this case, since the overcurrent flows in the transformer 1 and the impact pressure inside the transformer 1 is maintained for a predetermined time, the transformer 1 cannot be separated from the primary line 2 and the secondary line 3. This can cause a serious accident in the transformer 1.

In addition, the impact pressure relay 6 operates by the impact pressure at the time of an accident inside the transformer 1. In addition, it operates on the shock wave caused by the fault current of the secondary load of the transformer (1). Therefore, when the secondary side fault current flows through the winding of the transformer 1, the winding momentarily generates excessive electromechanical force, causing the winding to oscillate. If the shock wave generated by the flow of the insulating oil has a certain level or more, the impact pressure gauge Electricity 6 is operated.

However, in this case, since the impact pressure relay 6 operates even below a current that the transformer 1 can handle, an unnecessary trip signal is generated.

Then, since the transformer 1 is separated from the line even in a situation where it should be normally driven, there is a problem that the line side fault may be incorrectly recognized as a transformer failure.

Therefore, an object of the present invention is to solve the above problems, when a failure of the transformer external line is detected, the transformer to prevent the malfunction of the shock pressure relay by operating the shock pressure relay selectively to the magnitude of the external fault current The present invention provides an apparatus for preventing a malfunction of an impact pressure relay for a fire and a control method thereof.

According to a feature of the present invention for achieving the above object, an overcurrent relay operating in response to a transformer external line failure, an impact pressure relay operating in response to a transformer internal failure, the operation state and operation of the overcurrent relay and the impact pressure relay And a control unit configured to selectively generate a trip signal for controlling the operation of the transformer after determining the sequence and operation duration of the impact pressure relay.

The control unit is configured to generate no trip signal when the impact pressure relay returns to an initial state in which the impact pressure relay is inoperative within a time that can withstand the impact pressure generated inside the transformer even when the impact pressure relay operates later than the overcurrent relay. .

The control unit is configured such that a trip signal is always generated when the overcurrent relay is inoperative and the impact pressure relay is operated.

The control unit is configured such that a trip signal is always generated when the impact pressure relay is pre-operated than the overcurrent relay.

The control unit is configured to generate a trip signal at all times even when the impact pressure relay is operated after the overcurrent relay for more than the time that can withstand the impact pressure generated in the transformer.

The control unit is configured such that a trip signal is not generated when the impact pressure relay is inoperative.

According to another aspect of the invention, determining whether the first relay for detecting a transformer external line failure and the second relay for detecting the internal failure of the transformer and the operation sequence and the operation time duration of the second relay; And, as a result of the determination, while the second relay is operated later than the first relay, if the internal impact pressure of the second relay is extinguished within a predetermined time, controlling the trip signal for the second relay protection is not generated It is made, including.

The trip signal is generated when the second relay operates later than the first relay and the internal shock pressure of the second relay continues for a predetermined time or more.

The predetermined time is a time that can withstand the impact pressure generated inside the transformer.

The trip signal is generated when the first relay is inoperative and the second relay is in operation.

The trip signal is generated when the first relay operates later than the second relay.

When the first relay is in operation and the second relay is inoperative, the trip signal is not generated.

According to the shock pressure relay malfunction prevention device for a transformer and the control method configured as described above has the following effects.

That is, in a state where an overcurrent relay for switching according to a failure of an external line for a transformer and an impact pressure relay for detecting an internal fault of a transformer are configured, even if the impact pressure relay operates later than the overcurrent relay, the state of the impact pressure relay is within an initial state within a predetermined time. Since the trip signal does not occur when returning to, the malfunction of the impact pressure relay is minimized.

Hereinafter, a shock pressure relay malfunction prevention device for a transformer and a method of controlling the same according to the present invention will be described in detail with reference to a preferred embodiment shown in the accompanying drawings.

2 is a block diagram of a shock pressure relay malfunction prevention device for a transformer according to a preferred embodiment of the present invention.

Referring to the configuration of FIG. 2, an over current relay (OCR) or an over current ground relay (OCGR) 20 operating according to a current value of an external line of a transformer, and disconnecting a transformer from a line Shock pressure relay (SPR) 30 is provided for. The double overcurrent relay and ground fault overcurrent relay are relays that operate when the magnitude of the current exceeds a certain value. In particular, the ground overcurrent relay is a relay driven in response to the magnitude of the ground fault in the event of a ground fault. In this embodiment, only the overcurrent relay among the overcurrent relay and the ground overcurrent relay may be cited and described.

Also provided is a timer relay 40 that operates while counting the operating time of the impact pressure relay 30.

An overcurrent switch 50 and an SPR switch 96P for switching according to the overcurrent relay 20 and the impact pressure relay 30 are provided, and a timer switch 70 for switching according to the operation of the timer relay 40. Is provided.

Switching control unit 100 for generating a control signal to selectively generate a trip signal by the driving current and the driving sequence of the overcurrent relay 20 and the impact pressure relay 30, the time delay of the impact pressure relay operation (100) ) Is provided. The switching control unit 100 is configured in a control panel (Local Unit) of the transformer.

The trip signal generator 200 is configured to generate a trip signal by the control signal of the switching controller 100.

According to such a configuration, the switching control unit 100 prevents a malfunction of the impact pressure relay 30 by not generating a trip signal when the impact pressure inside the transformer disappears within a predetermined time even though an overcurrent flows through the transformer.

Hereinafter, the presence or absence of a trip signal will be described in detail with reference to respective circuits and timing diagrams according to whether the overcurrent relay and the impact pressure relay are driven and the driving sequence. In the circuit referred to in describing this, it should be noted that the overcurrent relay, the ground overcurrent relay, and the impact pressure relay are not shown, and only a switch for a relay that operates according to the relay driving is shown.

First, Figure 3 is a circuit diagram of an embodiment according to the malfunction prevention apparatus of the present invention.

The switching contact state shown in the circuit configuration of FIG. 3 is said to be an initial state in advance.

Looking at the configuration, the overcurrent relay switch 50a and the ground overcurrent relay switch 50Na are connected in parallel to the + and − input terminals to which a DC voltage source is connected. In the present embodiment circuit, two overcurrent relay switches and one ground overcurrent relay switch are used. One auxiliary relay 68X is connected to the overcurrent relay switch 50a and the ground overcurrent relay switch 50Na.

Switches 68Xa and 68Xb are provided to switch according to the auxiliary relay 68X. Among them, the switch 68Xa maintains a contact initial open state. Two 68Xa are provided, one of which 68Xa is connected in series with the timer relay 40 at the input terminal, and the other 68Xa is connected to the timer switch 40b connected to the relay 68X. The timer switch 40b is in the initial contact b closed state.

In the switch 68Xb, two switches are connected in series with a + input terminal, and a timer switch 40a for switching operation by the timer relay 40 is connected in parallel thereto. 40a is a contact initial open state.

The SPR switch 96P is connected to the + and-terminals. The SPR switch 96P uses a three-contact microswitch having an open / closed state to configure different circuit paths according to its operating state. In the figure, the state connected to the terminal side is an open state. An SPR seal-in relay 63X that operates according to the operating state of the SPR switch 96P is provided. SPR reset switches 63RS and SPR seal switches 63Xa and 63Xb are connected to both ends of the SPR seal relay 63X. 63Xa is the contact a initial open state, 63Xb is the contact b initial closed state.

On the other hand, a trip signal generator 200 for outputting a trip signal in accordance with each switch operation driven in accordance with the over-current relay, impact pressure relay, timer timer, the trip signal generator 200, the SPR seal The switch 63Xa which is an SPR seal which operates corresponding to the operation of the relay 63X, the switches 68Xa and 68Xb which operate in correspondence with the operation of the auxiliary relay 68X, and the timer switch 40a which operates by the operation of the timer relay 40 are provided. The switch 63Xa and the timer switch 40a, which are the SPR seals, are in a contact initial open state, the switch 68Xa is in a contact initial open state, and the switch 68Xb is in a b contact initial closed state.

In the initial malfunction prevention circuit configured as described above, a trip signal is selectively generated according to each driving state and order of the overcurrent relay, ground overcurrent relay, and impact pressure relay. The circuits of FIGS. 4 to 8 will be described below. This will be described with reference.

4 to 8 show the switch contact state changed from the switch state of the initial circuit according to the operation state and the operation sequence of the overcurrent relay and the impact pressure relay, and also shown in the timing diagram thereof.

Iii) overcurrent relay / Ground overcurrent relay  When not driven and only the shock pressure relay is in operation.

This will be described with reference to FIGS. 4A and 4B.

In the circuit diagram of FIG. 4A, the configurations of the overcurrent relay switch 50a and the ground overcurrent relay switch 50Na are not shown. That is because it is not driven.

As described above, when only the impact pressure relay 30 is operated, it is a case where the impact pressure is applied when an accident occurs inside the transformer, and a trip signal should be generated at this time.

Therefore, since the overcurrent relay or the ground overcurrent relay is in the undriven state, the overcurrent relay switch 50a and the ground overcurrent relay switch 50Na remain in the initial open state, and only the SPR switch 96P is in the closed state.

This activates relay 63X, the SPR seal. Accordingly, the switch 63Xa in the initial open state is in the closed state, and the switch 63Xb in the initial closed state is in the open state.

In this case, since the switch 63Xa connected to the trip signal generator 200 is also in the closed state, the trip signal generator 200 is operated through the switch 68Xb maintaining the initial closed state to generate a trip signal. .

4B, the overcurrent relay switch 50a, the ground overcurrent relay switch 50Na, and the timer relay 40 are all in an off state, but the shock pressure relay 30 operates at the 'A' time point. When only the t1 'time is turned on, the SPR switch 96P is correspondingly turned on.

Accordingly, the SPR real relay 63X is also turned on from the 'A' time point, and a trip signal is generated.

On the other hand, even if the SPR switch 96P is opened after the 't1' time, the SPR switch 96P is self-maintained until the SPR reset switch 63RS is operated by the SPR real relay 63X.

Ii) the impact pressure relay is an overcurrent relay or Than ground fault current relay  If it works fast.

This will be described with reference to FIGS. 5A and 5B.

In the circuit diagram of FIG. 5A, the configurations of the overcurrent relay switch 50a and the ground overcurrent relay switch 50Na are not shown. That is, since the SPR switch 96P operates first, since the operation of the overcurrent relay switch 50a and the ground overcurrent relay switch 50Na can be ignored.

The overcurrent relay or ground fault overcurrent relay is driven when a fault occurs outside the transformer. However, when the impact pressure relay operates before the overcurrent relay or the ground overcurrent relay, the transformer may explode because of an accident inside the transformer. Therefore, even in this case, a trip signal must be generated.

Therefore, the circuit is configured as in the case of i) above.

That is, referring to FIG. 5A, when the SPR switch 96P is closed according to the impact pressure relay 30, the SPR seal relay 63X is operated.

At this time, although the overcurrent relay or the ground overcurrent relay is driven in the circuit configuration, the auxiliary relay 68X (see FIG. 3) should be driven to change the switch 68Xb from the initial closed state to the open state, but the SPR switch 96P operates first. Therefore, the operation of the switch 68Xb is ignored.

Once the SPR seal relay 63X is operated, the switch 63Xa in the initial open state is in the closed state, and the switch 63Xb in the initial closed state is in the open state.

Therefore, since the switch 63Xa connected to the trip signal generator 200 is also in the closed state, the trip signal is generated via the switch 68Xb holding the initial closed state.

Referring to the timing diagram of FIG. 5B, when the overcurrent relay switch 50a or the ground overcurrent relay switch 50Na is driven in a closed state, the auxiliary relay 68X is also driven on.

However, if the SPR switch 96P is turned on for only 't1' time at 'A' before the overcurrent relay switch 50a or the ground overcurrent relay switch 50Na is driven on, the SPR seal relay 63X is also driven on. . Therefore, the trip signal continues to occur after the 'A' time. At this time, the relay 63X, which is the SPR seal, becomes undriven during the time 'T0' at which the timer is driven from the time when the auxiliary relay 68X is turned on.

In other words, when the overcurrent relay switch 50a or the ground overcurrent relay 50Na operates, the trip signal is generated when the SPR switch 96P operates earlier.

Iii) the shock pressure relay is an overcurrent relay or Than ground fault current relay  While operating late, the shock pressure inside the transformer T0 ) More than Lasting  If there is.

The circuit configuration of FIG. 6A and the timing diagram of FIG. 6B will be described together.

First, when the overcurrent relay or the ground overcurrent relay is operated before the shock pressure relay according to the detection of the external line failure of the transformer, the overcurrent relay switch 50a or the ground overcurrent relay switch 50Na is closed in the initial open state, and the auxiliary Relay 68X will be activated.

The state of the corresponding switches 68Xa and 68Xb also changes according to the auxiliary relay 68X operation. That is, the switch 68Xa is in the closed state in the initial open state, and the switch 68Xb is in the open state in the initial closed state. Here, after the overcurrent relay switch 50a or the ground overcurrent relay switch 50Na is operated, the SPR switch 96P also operates. However, even if the SPR switch 96P operates, the relay 63X, which is the SPR seal, is not driven. That is because power is not supplied.

Once in this state, the timer relay 40 operates at the 'A' time when the switch 68Xa is closed. When the timer relay 40 is in operation, its switch 40a is closed in the initial open state, and conversely 40b is in the open state in the initial closed state. Then, according to the closed state of the switching 40a, the relay 63X, which is the SPR seal, operates at the time 'A', whereby the 63Xa is in the closed state and the 63Xb is in the open state. At this time, the SPR switch 96P continues to operate for a 't1' time after 'T0'.

Therefore, the trip signal continues to occur after the 'A' time.

That is, when the timer relay 40 is driven and the SPR switch 96P is still in the on state even after the relay 63X, which is the SPR seal, is driven, the SPR switch 96P determines that an overcurrent flows in the transformer and the shock pressure inside the transformer is maintained to generate a trip signal. Will be generated.

Iii) the shock pressure relay is an overcurrent relay or Than ground fault current relay  While operating late, the shock pressure inside the transformer T0 ) If extinguished within.

The circuit configuration of FIG. 7A and the timing diagram of FIG. 7B will be described together.

First, when the overcurrent relay or the ground overcurrent relay is operated before the shock pressure relay according to the detection of the external line failure of the transformer, the overcurrent relay switch 50a or the ground overcurrent relay switch 50Na is closed in the initial open state, and the auxiliary Relay 68X will also operate.

The state of the corresponding switches 68Xa and 68Xb also changes according to the auxiliary relay 68X operation. That is, the switch 68Xa is in the closed state at the initial open state, and the switch 68Xb is in the open state at the initial closed state. At this time, after the overcurrent relay switch 50a or the ground overcurrent relay switch 50Na is operated, the SPR switch 96P also operates. However, even if the SPR switch 96P operates, the relay 63X, which is the SPR seal, is not driven. That is because power is not supplied.

Once the switch 68Xa is closed in this state, the timer relay 40 connected in series with the switch 68Xa is operated.

However, even if the SPR switch 96P is operated from the time when the overcurrent relay switch 50a or the ground overcurrent relay switch 50Na is operated before the time when the timer relay 20 starts to operate, the switch 40a is opened. The relay 63X, which is the SPR seal, does not operate because of the state. Therefore, the trip signal does not occur.

In other words, when an overcurrent flows through the transformer but the transformer internal shock pressure is extinguished within a predetermined time T0, it is determined that the transformer can withstand the environment and no trip signal is generated. Therefore, even in the case of a conventional external line failure, the shock pressure relay is operated to generate a trip signal, thereby minimizing the erroneous recognition that the shock pressure relay has malfunctioned.

Iii) overcurrent relay or Ground overcurrent relay  It works, but the shock pressure relay Inoperative  Occation.

This will be described with reference to FIGS. 8A and 8B.

In this case, as described above, when the overcurrent relay or the ground overcurrent relay is operated first in response to the failure of the transformer external line, the overcurrent relay switch 50a or the ground overcurrent relay switch 50Na is closed in the initial open state. The auxiliary relay 68X also operates.

The state of the corresponding switches 68Xa and 68Xb also changes according to the auxiliary relay 68X operation. That is, the switch 68Xa is in the closed state in the initial open state, and the switch 68Xb is in the open state in the initial closed state.

When the switch 68Xa is in the closed state, the timer relay 40 operates. When the timer relay 40 is operated, the switch 40a is in the closed state, and the switching 40b is in the open state.

However, when the impact pressure relay 30 is not operated, the SPR switch 96P is kept in the open state, and the relay 63X, which is the SPR seal, is inoperative, and thus the switch 63Xa is also kept in the open state, so that the trip signal is It does not occur.

As described above, according to the exemplary embodiment of the present invention, it is possible to determine whether the trip signal is generated according to whether the overcurrent relay, the ground overcurrent relay, the impact pressure relay are driven, the driving sequence thereof, and the operation duration of the impact pressure relay.

For example, when the shock pressure relay operates, a trip signal is generated as a whole to control the operation of the transformer to protect it. However, when the internal shock pressure occurs but disappears within a certain time (T0), the trip signal does not occur. Will be. If the impact pressure relay is inoperative, the trip signal does not occur unconditionally.

The trip signal generation condition according to this is summarized in the following [Table 1].

TABLE 1

Although described with reference to the illustrated embodiment of the present invention as described above, this is merely exemplary, those skilled in the art to which the present invention pertains various modifications without departing from the spirit and scope of the present invention. It will be apparent that other embodiments may be modified and equivalent. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

1 is a circuit diagram of a conventional shock pressure relay system for transformer protection.

2 is a block diagram of a shock pressure relay malfunction prevention device for a transformer according to a preferred embodiment of the present invention.

Figure 3 is an embodiment circuit diagram according to the malfunction preventing apparatus of the present invention.

4 to 8 are state circuit diagrams and timing diagrams in which switching contacts are changed according to driving states and sequences of an overcurrent relay, a ground fault current relay, and an impact pressure relay according to an exemplary embodiment of the present invention.

* Description of the symbols for the main parts of the drawings *

20: overcurrent relay, ground overcurrent relay

30: shock pressure relay 40: timer relay

50: overcurrent relay switch 70: timer switch

96P: SPR switch 100: switching control

200: trip signal generator

Claims (12)

An overcurrent relay operating in response to a fault in the transformer external line, An impact pressure relay operating in response to a fault inside the transformer, And a control unit configured to selectively generate a trip signal for controlling the operation of the transformer after determining the operation state and the operation sequence of the overcurrent relay and the impact pressure relay and the operation duration time of the impact pressure relay. Malfunction prevention device for shock pressure relay. The method of claim 1, The control unit is configured to generate no trip signal when the impact pressure relay returns to an initial state in which the impact pressure relay is inoperative within a time that can withstand the impact pressure generated inside the transformer even if the impact pressure relay operates later than the overcurrent relay. Malfunction prevention device for a shock pressure relay for a transformer, characterized in that. The method of claim 1, The control unit is configured to prevent a trip signal from occurring when the overcurrent relay is inactive and the impact pressure relay is in operation. The method of claim 1, And the control unit is configured to generate a trip signal whenever the impact pressure relay is pre-operated with the overcurrent relay. The method of claim 1, The control unit is configured to generate a trip signal at all times even when the impact pressure relay is operated after the overcurrent relay for more than the time that can withstand the impact pressure generated inside the transformer. Malfunction prevention device of impact pressure relay. The method of claim 1, And the control unit is configured to prevent a trip signal from occurring when the impact pressure relay is inoperative, thereby preventing a malfunction of the impact pressure relay for a transformer. Determining whether the first relay for detecting a transformer external line failure and the second relay for detecting a transformer internal failure, an operation sequence thereof, and an operation duration of the second relay; And, As a result of the determination, the second relay operates later than the first relay, and if the internal impact pressure of the second relay disappears within a predetermined time, controlling the trip signal for the second relay protection not to occur. Method for controlling the malfunction of the impact pressure relay for a transformer, characterized in that it comprises a. The method of claim 7, wherein And the trip signal is generated when the second relay operates later than the first relay and the internal shock pressure of the second relay continues for a predetermined time or more. The method according to claim 7 or 8, The predetermined time is a control method for preventing a malfunction of the impact pressure relay for a transformer, characterized in that the time to withstand the impact pressure generated in the transformer. The method of claim 7, wherein And the trip signal is generated when the first relay is inoperative and the second relay is in operation. The method of claim 7, wherein And a trip signal is generated when the first relay operates later than the second relay. The method of claim 7, wherein The trip signal is not generated when the first relay operates and the second relay is inoperative.

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