JPH09200950A - Transformer protection relay - Google Patents

Abstract

(57) [Summary] (Corrected) [Problem] Transformer protection that does not malfunction due to the exciting inrush current without providing an exciting inrush current countermeasure element in the accident detection relay, and that can quickly remove an internal accident of the transformer even during inspection. Provide a relay device. When an internal fault of a transformer occurs during inspection of a main detection relay unit, an AND condition is established in which an accident detection differential relay 9 operates, the undervoltage relay 8 operates, and the relay 9 does not operate. Return delay circuit 12 for extending a fixed time period
The output of is not generated and the breaker can be removed at high speed.
When an accident occurs outside the protection range of the transformer during inspection of the main detection relay unit, the voltage drops and the voltage recovers when the accident is removed. When an inrush current occurs, the output of the circuit 12 occurs and the relay 9 malfunctions. However, the breaker trip output does not occur. For the excitation inrush current during non-inspection of the main detection relay unit, the main detection differential relay 6 is subjected to the excitation inrush current countermeasure 7, and AND
Since the condition of the circuit 11 is not satisfied and the operation output of the relay 6 is absent, an erroneous output of tripping the breaker does not occur.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transformer protection relay device having a check circuit.

[0002]

2. Description of the Related Art In recent years, a transformer protective relay has generally been applied with a digital protective relay, and is composed of a main detection relay unit and an accident detection relay unit.
AN that is always the main detection relay operation and the accident detection relay operation
The breaker trip command is output according to the D condition. In addition, for inspection, one unit is inspected, and after the inspection is completed, the remaining units are inspected.

At this time, the inspection input is applied to the unit under inspection, and there is a possibility that the unit cannot operate if an accident occurs during inspection. However, if an accident occurs inside the transformer during inspection, the circuit breaker trip may have been performed after the inspection was cancelled, so the accident removal would be delayed and the tank could not cooperate with the explosion-proof curve of the transformer tank. There is a possibility of destruction and a fire. For this reason, during the inspection, the breaker trip command is output under the condition that the relay unit in the non-inspected relay unit operates independently. An example of this method will be specifically described with reference to FIG.

In FIG. 4, the current of each terminal of the transformer 1, which is present with the breaker 2 interposed between the primary bus and the secondary bus, passes through the current transformer 3 and the input converter 5 to the transformer. It is installed in the main detection relay unit and the accident detection relay unit of the protective relay. The main detection relay unit and the accident detection relay unit respectively house a main detection differential relay 6 and an accident detection differential relay 9 that perform differential calculation using each terminal current.

During the inspection of the main detection relay unit or the accident detection relay unit, the inspection signal is input to the auxiliary relay (TXM) 13A or the auxiliary relay (TXF) 13D through the OR circuit 19 and held in the operating state. Each of the auxiliary relay 13A and the auxiliary relay 13D has a normally open contact.

When the main detection relay unit is inspected, the auxiliary relay (TXM) 13A of the main detection relay unit is forcibly operated, its open contact is closed, and the accident detection differential relay 9 of the accident detection relay unit operates. The breaker trip command is output under the single condition of. On the contrary, when the accident detection unit is inspected, the auxiliary relay (TXF) 13D of the accident detection relay unit is forcibly operated, its open contact is closed, and the differential relay 6 of the main detection relay unit operates. The breaker trip command is output under certain conditions.

By the way, in a transformer protection relay device using a differential relay, it is necessary to take measures to prevent malfunction due to the transformer inrush current, but generally the second harmonic content in the differential current is When it is detected that the current is equal to or more than a certain value, it is determined as an exciting inrush current, and a process of locking the outputs of the main detection differential relay 6 and the accident detection differential relay 9 or increasing the suppression amount is adopted.

As a measure for preventing malfunction due to transformer excitation inrush current, in the example of FIG. 4, the second harmonic-containing detection element 7, NO in the main detection relay unit and the accident detection relay unit.
Each T circuit 10 is provided, and when the transformer exciting inrush current exists, the second harmonic content detecting element 7 indicates that the content rate of the second harmonic in the output of the input converter 5 is equal to or more than a certain value.
And the output together with the outputs of the main detection differential relay 6 and the accident detection differential relay 9 via the NOT circuit 10.
Although the condition is taken by the D circuit 11, since the AND condition is not satisfied, it is determined as the exciting inrush current, and the output of the main detection differential relay 6 or the accident detection differential relay 9 is locked to lock the auxiliary relay 1
It does not operate 3A or 13D. Therefore, the breaker trip command is not output.

If there is no transformer exciting inrush current and the content rate of the second harmonic in the output of the input converter 5 is below a certain value, one condition of the AND circuit 11 is satisfied, If the output of the main detection differential relay 6 or the accident detection differential relay 9 which is the other condition exists, the auxiliary relay 13A is present.
Alternatively, 13D is operated. Therefore, the breaker trip command is output.

[0010]

As described above, in the case of the construction in which the cutoff output is output under the condition that the differential relay of the unit which is not inspected during the inspection is operated independently, the measures against the exciting inrush current are applied to both the main detection relay and the accident detection relay. Will need to be implemented. Therefore, the configuration of the accident detection relay also has a heavy processing load for the countermeasure against the inrush current, and as a result, the analog input section, the relay calculation section, and the sequence processing section cannot be accommodated in one or two boards, It is unavoidable to adopt a hardware configuration equivalent to that of the main detection relay unit in which the analog input section, the relay calculation section, and the sequence processing section are independent board configurations. This hinders the downsizing of transformer protection relay devices and the improvement of maintainability.

Therefore, in view of the above problems, an object of the present invention is to provide a simple accident detection relay structure without providing the accident detection relay with a complicated function such as determination of the second harmonic content rate, and to perform inspection. It is an object of the present invention to provide a transformer protection relay device which does not malfunction due to an inrush current of an excitation and does not impair the original protection function even if a circuit for performing trip output of a circuit breaker is provided under a single condition of an accident detection relay operation.

[0012]

In order to achieve the above-mentioned object, the present invention provides a transformer protection relay device according to claim 1 of the present invention, which has an inspection function, and an accident detection relay has transformer terminals. In a transformer protection relay device that uses a differential relay that configures differential protection by current, and uses a differential relay that configures differential protection by the transformer each terminal current in the main detection relay,
Transformer: A circuit having an undervoltage relay that detects a decrease in the tertiary bus voltage, a signal circuit that outputs a signal due to the fault detection relay failure and the undervoltage relay operation, and a circuit that delays the restoration of the output of the signal for a certain period of time. And a circuit for outputting a circuit breaker trip command by the operation of the accident detection relay, provided that the main detection relay is under inspection and no signal is output from the delay circuit.

A transformer protection relay device according to a second aspect of the present invention has an inspection function and uses a current balancing relay that uses an excitation winding current and a tap winding current as a fault detection relay, and uses a main detection relay. In a transformer protection relay device using a current balancing relay that uses excitation winding current and tap winding current in
Transformer: A circuit having an undervoltage relay that detects a decrease in the tertiary bus voltage, a signal circuit that outputs a signal due to the fault detection relay failure and the undervoltage relay operation, and a circuit that delays the restoration of the output of the signal for a certain period of time. And a circuit for outputting a breaker trip command by the operation of the accident detection relay on condition that the main detection relay is under inspection and no signal is output from the delay circuit.

A transformer protection relay device according to a third aspect of the present invention has an inspection function and uses a differential relay which constitutes differential protection by each terminal current of the transformer as an accident detection relay, and uses a main detection relay. In the transformer protection relay device using the differential relay that configures the differential protection by the transformer each terminal current,
A signal circuit that has an undervoltage relay that detects a decrease in the voltage of the tertiary bus of the transformer, outputs a signal due to the malfunction of the accident detection relay and the operation of the undervoltage relay, and outputs the signal to the main detection relay during inspection. A circuit that is provided with a circuit for holding during inspection, and outputs a breaker trip command by the operation of the accident detection relay, provided that the main detection relay is in inspection and there is no signal output from the holding circuit. And consisted of

A transformer protection relay device according to a fourth aspect of the present invention has an inspection function, and uses a current balancing relay using an excitation winding current and a tap winding current as an accident detection relay, and uses a main detection relay. In a transformer protection relay device using a current balancing relay that uses excitation winding current and tap winding current in
A signal circuit that has an undervoltage relay that detects a decrease in the voltage of the tertiary bus of the transformer, outputs a signal due to the malfunction of the accident detection relay and the operation of the undervoltage relay, and outputs the signal to the main detection relay during inspection. A circuit that is provided with a circuit for holding during inspection, and outputs a breaker trip command by the operation of the accident detection relay, provided that the main detection relay is in inspection and there is no signal output from the holding circuit. And consisted of

A transformer protection relay device according to a fifth aspect of the present invention has an inspection function, and uses a current balancing relay that uses an excitation winding current and a tap winding current as the fault detection relay, and uses the main detection relay. In a transformer protection relay device using a current balancing relay that uses excitation winding current and tap winding current in
It has an undervoltage relay that detects a decrease in the primary bus voltage of the transformer or the secondary bus voltage of the transformer, and outputs a signal circuit and a signal circuit that outputs a signal due to the failure of the fault detection relay and the operation of the undervoltage relay. The main detection relay is provided with a circuit that is held during the inspection under the condition that the main detection relay is being inspected, and there is no signal output from the holding circuit. It is composed of a circuit that outputs a trip command.

With the above-mentioned structure, the transformer protection relay device of the present invention operates in the same manner as the operation of the main detection relay during non-inspection.
The breaker trip command is output according to the AND condition of the operation of the fault detection relay that does not have the function of preventing the inrush of excitation such as the harmonic content detection element. If an internal accident in the transformer occurs during inspection of the main detection relay unit, the accident detection relay unit's accident detection relay detects the drop in the bus voltage because the relay operates, and the fault detection relay unit's accident detection The output of the circuit that extends the output that is satisfied under the condition that the relay does not operate for a certain period of time does not occur, and the breaker can be tripped at high speed.

In addition, there is a possibility that an accident occurs outside the transformer protection range during inspection of the main detection relay unit, the voltage drops, and the voltage recovers when the accident is removed, which may cause an inrush current. Output of the circuit that extends the output that is established under the condition that the relay is operating and the fault detection relay unit fault detection relay is inactive for a certain period of time, and is cut off even if the fault detection relay unit fault detection relay malfunctions. No device trip command is output.

On the other hand, the output condition of the breaker trip command is the AN of the operation of the main detection relay and the operation of the accident detection relay for the exciting inrush current during non-inspection of the main detection relay unit.
D condition is met, but because the main detection relay of the main detection relay unit is provided with measures against the inrush current and the main detection relay does not output an operation output, the AND condition is not satisfied and the erroneous output of the breaker trip does not occur. .

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a transformer protection relay device of the present invention will be specifically described with reference to FIG.
In FIG. 1, the same parts as those shown in FIG. 4 are designated by the same reference numerals. As shown in FIG. 1 and FIG. 4, an undervoltage relay 8 for detecting a decrease in the tertiary bus voltage is provided, and the undervoltage relay operates and the accident detection differential relay 9 of the accident detection relay unit does not operate. Is provided as an AND condition, and includes a return delay circuit 12 that extends the output for a certain period of time, and the return delay circuit 1 is provided during inspection of the main detection relay unit.
2 is the same as that of FIG. 4, except that the circuit configuration outputs a circuit breaker trip command on the condition that the output of No. 2 does not exist and that the accident detection relay 9 operates.

Further, the accident detection differential relay 9 of the accident detection relay unit is a differential relay which is not equipped with a function for preventing the inrush of excitation such as detection of the second harmonic content rate. Then, the auxiliary relay (TXM) 13A, the auxiliary relay (11X
M) 13B, auxiliary relay (TXF) 13D, auxiliary relay (11XF) 13E are relays having a normally open contact,
The auxiliary relay (TLX) 13C is a relay having a normally closed contact.

Each terminal current of the transformer 1 is taken in from the instrument current transformer 3 to the transformer protection relay device 14, the tertiary bus voltage is similarly taken in from the instrument transformer 4, and the input converter 5 is used.
It is introduced to the main detection relay unit and the accident detection relay unit via. The output of the main detection differential relay 6 of the main detection relay is an auxiliary relay (TX) on condition that the output of the second harmonic content detection element 7 does not exist.
M) Drive 13A.

On the other hand, the accident detection relay 9 is an auxiliary relay (TX) without any measures against the excitation inrush current such as detection of the second harmonic content rate.
F) Drive 13D. Further, the auxiliary relay (TLX) 13C is driven by the AND condition that the undervoltage relay 8 operates and the accident detection relay 9 does not operate, and the output thereof is extended by the return delay circuit 12 for a predetermined time period.
Further, 11XM is an auxiliary relay 13B which is driven during the inspection of the main detection relay unit, and 11XF is an auxiliary relay 13E which is driven during the inspection of the accident detection relay unit.

During non-inspection, the auxiliary relay (TXM) 13A driven by the operation output of the main detection relay 6 and the auxiliary relay (TX) driven by the operation output of the accident detection relay 9
F) Due to the operation of 13D, the auxiliary relay (TX
The normally open contacts of M) 13A and auxiliary relay (TXF) 13D are closed, and a breaker trip command is output. At this time, the operating condition of the auxiliary relay (TXM) 13A includes the condition of the countermeasure against the exciting inrush current.

That is, when the transformer exciting inrush current is present, the second harmonic wave content detecting element 7 detects that the content rate of the second harmonic wave in the output of the input converter 5 is a certain value or more. , Its output is conditioned by the AND circuit 11 together with the output of the main detection differential relay 6 via the NOT circuit 10, but AN
Since the D condition is not established, it is judged as the exciting inrush current, and the output of the main detection differential relay 6 is locked to lock the auxiliary relay (TXM).
It does not operate 13A. Therefore, the normally open contact of the auxiliary relay (TXM) 13A remains open, and the breaker trip command is not output.

If there is no transformer inrush current,
If the second harmonic content detecting element 7 detects that the content rate of the second harmonic in the output of the input converter 5 is equal to or less than a certain value, one condition of the AND circuit 11 is satisfied and the other condition is satisfied. If there is an output of the main detection differential relay 6 that is, the AND condition is satisfied and the auxiliary relay (TXM) 13A is operated. Therefore, the normally open contact of the auxiliary relay (TXM) 13A is closed, and the breaker trip command is output.

During the accident detection relay unit inspection,
The auxiliary relay (11XF) 13E operates and its normally-open contact is closed, and the breaker trip command is output by the operation of the auxiliary relay (TXM) 13A driven by the operation output of the main detection differential relay 6. Also in this case, auxiliary relay (TXM)
The operating condition of 13A includes the above-mentioned condition for the countermeasure against the inrush current of the excitation.

On the other hand, when the main detection relay unit is being inspected, the auxiliary relay (11XM) 13B is operating, so the normally open contact of the auxiliary relay (11XM) 13B is closed. When the accident detection differential relay 9 operates immediately due to an internal accident of the transformer, the condition of the AND circuit 11 is not satisfied, so that the auxiliary relay (TLX) 13C does not operate and its contact remains closed, and the auxiliary relay ( By the operation of the TXF) 13D, the normally open contact of the auxiliary relay (TXF) 13D is closed, and the breaker trip command is output.

When a voltage drop occurs due to an accident outside the transformer protection range during inspection of the main detection relay unit, the undervoltage relay 8 detects and outputs it, and the condition of the AND circuit 11 is satisfied and the auxiliary relay ( Since the TLX) 13C operates, the normally closed contact of the auxiliary relay (TLX) 13C is opened, and even if the accident detection differential relay 9 operates due to the exciting inrush current due to the subsequent recovery of the accident removal voltage, the auxiliary relay ( Since the normally closed contact of the TLX) 13C is opened, the trip command is output locked, so that the circuit breaker trip command is not erroneously output.

As a result, even if the accident detection differential relay 9 does not have a complicated countermeasure against the inrush current such as the detection of the second harmonic content ratio, it does not malfunction due to the inrush current, and it can prevent the accident during the inspection. The breaker trip command can be output at high speed.

Another embodiment of the transformer protection relay device of the present invention is shown in FIG. 2 is replaced with the main detection differential relay 6 and the accident detection differential relay 9 in the transformer protection relay device of the present invention shown in FIG. 1, and the current of the excitation winding 16 and the tap winding of the transformer 1 are replaced. This is a case where the main detection current balance relay 17 and the fault detection current balance relay 18 which detect a failure of the winding due to the imbalance of the current of the line 15 are applied. The other configurations and numbers of circuit elements are the same as those in FIG.

This accident detection current balance relay 18 also needs a countermeasure against the excitation inrush current, but like the case of FIG. 1, when the conditions of the operation of the undervoltage relay 8 and the failure detection current balance relay 18 are not satisfied, the conditions are satisfied. By combining the recovery delay circuit 12 which is a circuit that extends the output for a certain period of time, even if the magnetizing inrush current countermeasure is not added to the fault detection current balancing relay 18,
It is possible to output the breaker trip command at high speed during an internal accident of the transformer even if the malfunction does not occur due to the inrush current of excitation. Since the operation for each accident during non-inspection and during inspection is the same as in the embodiment of FIG. 1,
Here, the description is omitted.

Another embodiment of the transformer protection relay device of the present invention is shown in FIG. In the configuration shown in FIG. 3, instead of the recovery delay circuit 12 shown in FIG. 1 or 2, an output is provided when the AND condition that the undervoltage relay 8 is operating and the accident detection differential relay 9 is inoperative is satisfied, This is an example of a circuit that holds the main detection relay unit depending on the condition during inspection. The other circuit configuration is the same as that of FIG. 1 or FIG.

The output of the operation of the undervoltage relay 8 and the failure of the fault detection differential relay 9 due to the satisfaction of the condition in the AND circuit 11A is passed through the OR circuit 19, and the condition under inspection of the main detection relay unit and the AND circuit 11B are checked. When the condition is satisfied, the auxiliary relay (TLX) 13C is driven to output and at the same time O
It is input to the R circuit 19. For this reason, the auxiliary relay (TL
X) 13C is driven and held. The other operations for the exciting inrush current and the operation for the transformer internal accident are exactly the same as those described with reference to FIGS. 1 and 2, and therefore the description thereof is omitted here.

Further, in the above description, the voltage detected by the undervoltage relay 8 is described as detecting the decrease in the tertiary bus voltage, but the decrease in the primary bus voltage may be detected, or A configuration may be adopted in which a drop in the secondary bus voltage is detected or a drop in each terminal voltage due to an instrument transformer installed on the transformer terminal side of the circuit breaker 2 is detected. Does not change.

[0036]

As described above, according to the present invention, a simple accident detection relay structure can be provided without providing a complicated excitation inrush current countermeasure element such as second harmonic content rate determination in the accident detection relay. Even if it becomes a circuit that outputs a circuit breaker trip command based on the single operation condition of the fault detection relay during inspection, it does not malfunction due to the inrush current of the excitation, and even if it is during inspection, it will not cause an internal accident in the transformer. Accidents can be removed at high speed,
It is possible to provide a transformer protection relay device that is downsized and has improved maintainability.

[Brief description of drawings]

FIG. 1 is a configuration diagram illustrating a configuration of the present invention.

FIG. 2 is a configuration diagram showing another embodiment of the present invention.

FIG. 3 is a configuration diagram showing another embodiment of the present invention.

FIG. 4 is an explanatory view of a conventional device.

[Explanation of symbols]

 1 Transformer 2 Circuit breaker 3 Current transformer (CT) for instrument 4 Transformer (PT) for instrument 5 Input converter 6 Main detection differential relay 7 Second harmonic content detection element 8 Undervoltage relay 9 Fault detection differential Relay 10 NOT circuit 11 AND circuit 12 Return delay (off-delay) circuit 13 Auxiliary relay 14 Transformer protection relay device 15 Tap winding 16 Excitation winding 17 Main detection current balance relay 18 Fault detection current balance relay 19 OR circuit

Claims (5)

[Claims] 1. A differential relay having an inspection function, wherein the accident detection relay uses a differential protection configured by the transformer terminal currents, and the main detection relay uses a differential protection configured by the transformer terminal currents. In a transformer protection relay device using a dynamic relay, a signal circuit that has an undervoltage relay that detects a decrease in a transformer third bus voltage, and outputs a signal by the fault detection relay operation and the undervoltage relay operation. And a circuit for delaying the restoration of the output of the signal for a certain period of time, provided that the main detection relay is under inspection and there is no signal output of the delay circuit, the circuit breaker is pulled by the operation of the accident detection relay. A transformer protection relay device having a circuit for outputting a removal command. 2. A current balancing relay having an inspection function, which uses an exciting winding current and a tap winding current as an accident detection relay, and uses an exciting winding current and a tap winding current as a main detection relay. In a transformer protection relay device using a balanced relay, a signal circuit that has an undervoltage relay that detects a decrease in transformer tertiary bus voltage, and outputs a signal by the fault detection relay operation and the undervoltage relay operation. And a circuit for delaying the restoration of the output of the signal for a certain period of time, provided that the main detection relay is under inspection and there is no signal output of the delay circuit, the circuit breaker is pulled by the operation of the accident detection relay. A transformer relay relay device having a circuit for outputting a removal command. 3. A differential relay having an inspection function, wherein the accident detection relay uses a differential protection by each terminal current of the transformer, and the main detection relay uses a differential protection by each terminal current of the transformer. In a transformer protection relay device using a dynamic relay, a signal circuit that has an undervoltage relay that detects a decrease in a transformer third bus voltage, and outputs a signal by the fault detection relay operation and the undervoltage relay operation. And a circuit for holding the output of the signal during the inspection under the condition that the main detection relay is being inspected, and if the main detection relay is inspecting and there is no signal output of the holding circuit, the accident A transformer protection relay device having a circuit for outputting a breaker trip command according to a detection relay operation. 4. A current balancing relay having an inspection function, which uses an excitation winding current and a tap winding current as an accident detection relay, and an excitation winding current and a tap winding current as a main detection relay. In a transformer protection relay device using a balanced relay, a signal circuit that has an undervoltage relay that detects a decrease in transformer tertiary bus voltage, and outputs a signal by the fault detection relay operation and the undervoltage relay operation. And a circuit for holding the output of the signal during the inspection under the condition that the main detection relay is being inspected, and if the main detection relay is inspecting and there is no signal output of the holding circuit, the accident A transformer protection relay device having a circuit for outputting a breaker trip command according to a detection relay operation. 5. An undervoltage relay for detecting a drop in the transformer primary bus voltage or a transformer secondary bus voltage, in place of the undervoltage relay for detecting a drop in the transformer tertiary bus voltage. The transformer protection relay device according to claim 1, claim 2, claim 3 or claim 4.