JPH02106131A - Protection and coordination system for distribution line - Google Patents

Abstract

PURPOSE:To improve the reliability of a protective relay by performing opening function of a circuitbreaker through a protective relay arranged for a high voltage power receiving facility only when ground fault is detected both in the high voltage power receiving facility and a substation. CONSTITUTION:High voltage power receiving facilities 4 are arranged for respective branch lines 3 from a main line 2 for feeding power from a substation 1, where a master station 6 is arranged in the substation 1 while slave stations 5 for communicating signals with the master station 6 are arranged in respective high voltage power receiving facilities 4 receiving power from the substation 1. When a ground fault detector Ry2 arranged in the high voltage power receiving facility 4 detects ground fault and detection of ground fault is also confirmed at the substation 1 side through communication of signals between the master station 6 and the slave station 5, opening function of a circuitbreaker CB 2 is carried out through the protective relay at the high voltage power receiving facility 4. Since the circuitbreaker CB 2 is not opened through erroneous function of the protective relay caused by noise such as radio wave, reliability of the protective relay at the high voltage power receiving facility 4 can be improved.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a protection coordination system for power distribution lines.

[Conventional technology] When a fault such as a ground fault or short circuit occurs in a power system, it must be promptly detected and appropriate measures taken, such as isolating the faulty section, to restore the system to a normal state. Therefore, substations and high-voltage power receiving equipment are each equipped with a protective relay that detects a ground fault and activates the necessary circuit breakers. Conventionally, protection coordination between protective relays in substations and high-voltage power receiving equipment has been performed based on time differences or differences in ground fault current setting values.

[Problems to be Solved by the Invention] However, in the conventional protection coordination method, the protective relay of the high-voltage power receiving equipment operates independently of the protective relay of the substation when a current larger than a set value flows. Since high-voltage power distribution lines are usually ungrounded, the ground fault current is very small compared to the short-circuit current. Therefore, the setting value of the protective relay of the high-voltage power receiving equipment is small, and the radio waves emitted near the high-voltage power receiving equipment The protective relay operates even though no ground fault has occurred due to noise such as
There was a problem that the reliability of the system was low.

The present invention has been made in view of the above-mentioned problems, and its purpose is to operate the protective relay of high-voltage power receiving equipment only when a ground fault actually occurs. An object of the present invention is to provide a protection coordination method for power distribution lines that can improve reliability.

[Means for resolving the order of assignments] In order to achieve the above object, the present invention provides a master station in a substation, and sends and receives signals to and from the master station in each high-voltage power receiving equipment to which power is supplied from the substation. If a ground fault detection device installed in the high voltage power receiving equipment detects a ground fault,
When it is confirmed that a ground fault has been detected on the substation side by exchanging signals between the slave station and the master station, the circuit breaker is opened by the protective relay of the high voltage power receiving equipment.

[Operation] In the present invention, the protective relay does not operate even if the ground fault detection device installed in the high-voltage power receiving equipment detects a ground fault, and the signal between the slave station installed in the high-voltage power receiving equipment and the master station of the substation is not activated. Only when the slave station confirms that a ground fault has been detected on the substation side during transmission and reception, that is, when a ground fault is detected on both the high-voltage power receiving equipment and the substation, will the protective relay installed in the high-voltage power receiving equipment interrupt the operation. An opening operation of the container is performed.

[Example 1] Hereinafter, an example in which the present invention was co-produced will be described with reference to the drawings.

Each high-voltage power receiving facility 4 is provided on a branch line 3 from a main line 2 that supplies power from a substation 1 .

Substation 1 has 2I! which opens and closes the main line! Earth fault relay R that detects ground faults using disconnector CB1 and zero-phase current transformer ZCTI
yl is provided to constantly monitor changes in the current value flowing through the main line 2. In addition, a ground fault occurrence signal is input from the ground fault m electric appliance Ryl to the substation 1, and each high voltage power receiving equipment 4
A master station 6 is provided for exchanging signals with a slave station 5 provided at the base station.

Each high-voltage power receiving equipment 4 has a ground fault relay Ry2 as a ground fault detection device that detects a ground fault fault by a zero-phase current transformer ZCT2 provided in the branch line 3 between the circuit breaker CB2 and the transformer 7.
A slave station 5 is also provided for transmitting and receiving signals to and from a master station 6 provided at the substation I. This ground fault M1 electric appliance Ry2 operates in about 0.4 seconds when a ground fault current of more than the set value (0.2 A in this embodiment) flows in the branch line 3, and the ground fault detection signal H It is designed to output .

Further, the high-voltage power receiving equipment 4 is provided with an AND circuit 8 to which the ground fault detection signal L (and the ground fault confirmation signal G input from the master station 6 of the substation 1 via the slave station 5) is input. When a signal is output from the AND circuit 8, the tripping coil 9 of the circuit breaker CB2 is excited and the circuit breaker CB2 is opened.

Furthermore, the slave station 5 receives a ground fault detection signal H from the ground fault relay Ry2.
When is output, a ground fault L raw signal K is sent to the master station 6,
At the substation 1111I, when the master station 6 receives the ground fault occurrence signal K, the high voltage power receiving equipment is activated even within the substation 1! 4, an AND circuit 10 is provided which inputs the ground fault detection signal from the ground fault relay Ryl into one terminal, and based on this AND condition, the master station 6 confirms the ground fault from the slave station 5. Signal G
is now output. Signals are exchanged between the slave station 5 and the master station 6 using, for example, a microwave line.

In this embodiment, the ground fault current setting value on the substation 1 side is 0.8 to 1. The operating time of the ground fault relay Ryl is set to about 0.8 to 1 second, and in the event of a ground fault on the branch line side, the circuit breaker C on the high voltage power receiving equipment side will be activated.
Substation side circuit breaker CBI does not open before B2.

Next, protection coordination of the power distribution line configured as described above will be explained.

Now, when a ground fault occurs on the power receiving side of the high voltage power receiving equipment 4 and a ground fault detection signal H is output from the ground fault relay Ry2,
A signal H is input to one terminal 8a of the AND circuit 8, and a ground fault occurrence signal K is transmitted from the slave station 5 to the master station 6. Based on the reception of the ground fault occurrence signal from the slave station 5, confirmation of the occurrence of a ground fault is also carried out within the substation 1, and this ground fault occurrence signal is combined with the ground fault detection signal of the ground fault relay Ryl on the substation 1 side. When the AND condition in the AND circuit IO is satisfied, a ground fault confirmation signal G is transmitted from the master station 6 to the slave station 5.

As a result, the belief G is also input to the other terminal 8b of the AND circuit 8 of the high-voltage power receiving equipment 4, the AND condition is established, and the signal M is output from the AND circuit 8. And this signal M
As a result, the tripping coil 9 of the circuit breaker CB2 is energized, and the circuit breaker CB2 is opened.

If the circuit breaker CB2 is not opened due to a defect in the ground fault relay R5r2 on the high voltage power receiving equipment 4 side or for other reasons, and a ground fault is detected at the substation 1 even after a predetermined period of time has elapsed, the substation 1 The protective relay is activated and circuit breaker C of substation 1 is activated.
DI will be released. In addition, if a ground fault occurs in the main line 2, the ground fault relay Ry2 on the high-voltage power receiving equipment 4 side cannot detect the ground fault, so the protective relay at the substation 1 is activated and the return switch CDI at the substation 1 is activated. will be released.

In addition, even when no ground fault has occurred, a ground fault detection signal (1) from the ground fault relay Ry2 on the high voltage power receiving equipment 4 side due to noise etc.
When is output, the signal ) is inputted to one terminal 8a of the AND circuit vPI 8, and a ground fault occurrence signal K is transmitted from the slave station 5 to the master station 6.

In this case, since no ground fault has actually occurred, the substation I
In IIWI, a ground fault is not detected and the ground fault confirmation signal G is not input to the other terminal 8b of the AND circuit 8. Therefore, the AND condition of the AND circuit 8 is not satisfied and the circuit breaker C
The circuit breaker CBI is not opened by excitation of the BI tripping coil 9.

[Effects of the Invention] As described in detail below, according to the present invention, when the ground fault detection device of the high-voltage power receiving equipment detects a ground fault, only when a ground fault is also detected on the substation side. Since the protective relay on the high-voltage power receiving equipment side operates and opens the circuit breaker, the circuit breaker will not be accidentally opened due to malfunction of the protective relay due to noise such as radio waves, and the reliability of the protective relay of the high-voltage power receiving equipment will be improved. It gets expensive.

[Brief explanation of drawings]

The figure is a schematic diagram showing an embodiment of the present invention in an elongated form. Substation 1, high voltage power receiving equipment 4, slave station 5, master station 6, circuit breaker C
l31, ground fault relay Ryl as a ground fault detection device.

Claims (1)

[Claims] 1. A master station is installed in the substation, and a slave station is installed in each high-voltage power receiving equipment that receives power from the substation to send and receive signals from the master station, and the ground fault detection device installed in the high-voltage power receiving equipment detects a ground fault. If a ground fault is detected on the substation side by sending and receiving signals between the slave station and the master station, the circuit breaker shall be opened by the protective relay of the high-voltage power receiving equipment. Features a distribution line protection coordination system.