CN108808832A - A kind of band small power supply access system prepared auto restart application enhancements method - Google Patents

Abstract

The invention belongs to the technical field of relay protection, and provides an improvement method for the application of standby automatic switching in a system with a small power supply access, which solves the defects of traditional standby automatic switching in the application of traditional substations and intelligent substations. When the line fails, the present invention sends a "long-jump signal" through the differential protection device on the opposite side of the line to control the differential protection device on the local side to ensure that the circuit breaker on the local side can trip in time when a fault occurs, thereby ensuring the correct operation of the standby automatic switch .

Description

A method for improving the application of backup and automatic switching in a system with small power supply access

technical field

The invention belongs to the technical field of relay protection, and in particular relates to an improved method for the application of self-switching of a system with a small power access.

Background technique

When serious situations such as permanent faults, misoperations by personnel, or incorrect actions of primary and secondary equipment occur during the operation of the power grid, the backup power self-injection device will operate. If in this case, the standby automatic switching device still cannot operate reliably, the scope of power outage will be expanded. Therefore, in the event of a system failure or accident, it is necessary to resolutely prevent the backup power automatic switching device from refusing to operate, which will cause the scope of power outage to expand. Therefore, in the design of the circuit and logic programming of the self-injection device, it is necessary to consider sufficient starting volume as much as possible, and improve various action logics to improve reliability and sensitivity. At present, the ring network design and the open-loop backup operation mode are widely used in the 110kV power grid.

Contents of the invention

Aiming at the deficiencies of the prior art, the present invention provides a method for improving the application of automatic switch-on of the access system with a small power supply.

A method for improving the application of backup self-switching with a small power supply access system, the system includes line 1 as the working power supply of the substation, busbar I and busbar II as the main network of the system, and line 2 as a backup; when the substation is connected to a small When the power supply is on, line 1 and line 2 are connected to the main network of the system through circuit breakers 1DL and 2DL respectively, and the small power supply is connected to the main network through circuit breaker 4DL, and circuit breaker 4DL is in the closed state; circuit breaker 2DL is in the hot standby state;

In the improved method, the protection devices on both sides of the line are differential protection devices; the small power supply is also equipped with corresponding protection devices;

The improved method is to send a "long-jump signal" to the protection device on the substation's side through the protection device on the opposite side of the line, disconnect the circuit breaker 4DL connected to the small power supply, and then ensure the correct operation of the standby automatic switching; A block reclosing command is issued, at this time the circuit breaker 1DL is disconnected, 2DL is connected, the bus of the substation is de-energized, and the standby automatic switch operates correctly and reliably.

The improvement scheme of the present invention includes an improvement scheme for the automatic switching of the central standby of the conventional substation and an improved method for the application of the automatic switching of the central standby of the intelligent substation.

The access system with a small power supply applied in the present invention includes a line 1, a bus I, a small power supply connected to the bus I, a bus II and a line 2 as a backup. When the 110kV substation is connected to a regional small power source (such as a 10kV power plant or a 110kV power plant), the standby automatic switching device may refuse to operate. As shown in Figures 1-3, there are three 110kV incoming lines on the 110kV bus of the substation. Line 1 and Line 2 are connected to the system power grid through circuit breakers 1DL and 2DL respectively, and regional power plants are connected to the main grid through circuit breaker 4DL. The circuit breaker 4DL is in the closed state; the line 1 is used as the working power supply of the substation, the line 2 is the standby power supply, and the circuit breaker 2DL is in the hot standby state. If there is a permanent fault on line 1, the switch on the opposite side of line 1 will trip, and the backup self-switching will start a logical judgment. At this time, since the 110kV power plant is still supplying power, it may cause the bus voltage to not drop rapidly and fail to reach the fixed value of "bus voltage loss", and the standby power switch will be activated. The power supply of the whole station is provided by the power plant. Due to the power shortage caused by the output of the power plant, the low-cycle load shedding protection action will expand the accident.

For above-mentioned situation, the present invention provides a kind of improvement scheme in conventional substation, and this improvement scheme comprises the following steps:

Step 1: When a fault occurs on line 1, when the differential protection device on the opposite side operates (differential protection or other backup protection action), at the same time send a "long jump signal" to the differential protection device on this side;

Step 2: The "remote jump signal" controls the action of the relay contact of the differential protection device on this side, disconnects the circuit breaker connected to the small power supply (power plant), and at the same time sends a blocking and reclosing command to the protection device on the small power supply side;

Step 3: When the busbar of the substation loses power, the standby automatic switch operates correctly and reliably to ensure the safe operation of the substation.

The present invention also provides a kind of improvement scheme in intelligent substation, and this improvement scheme comprises the following steps:

Step 1: When a fault occurs on line 1, when the intelligent protection device on the opposite side acts (differential protection or other backup protection action), a "long jump signal" is sent to the intelligent protection device on this side at the same time;

Step 2: "Long-jump signal" starts the intelligent protection device on this side and sends a trip command directly to the intelligent terminal on the side of the small power supply line through GOOSE point-to-point, and at the same time sends a blocking and reclosing command to the protection device on the power supply side through the GOOSE network;

Step 3: When the busbar of the substation loses power, the standby automatic switch operates correctly and reliably to ensure the safe operation of the substation.

Beneficial effect:

The invention proposes an improvement plan for the potential hidden danger of standby self-switching and refusal to operate in the access system with a small power supply, so as to prevent the expansion of accidents and further enhance the reliability of the power grid.

Description of drawings

Figure 1 is the conventional substation improvement scheme.

Figure 2 is the smart substation improvement plan.

Fig. 3 is a working principle diagram of the present invention.

Detailed ways

The specific embodiments of the present invention will be further described below in conjunction with the accompanying drawings.

The conventional substation improvement scheme is shown in Figure 1. Differential protection 1 is the differential protection device on the local side, differential protection 2 is the differential protection device on the opposite side, CJ1 is the protection trip contact, CJ2 is the protection trip auxiliary contact, LP1 In order to protect the hard pressure plate for tripping, LP2 is a hard pressure plate for joint cut (it can also be used to drive the joint cut function of standby automatic switching). The CJ1 contact controls the tripping of the circuit breaker 1DL, and the CJ2 contact controls the tripping of the circuit breaker 4DL. 1DL, 3DL, 4DL, 5DL, 6DL are in closing position, 2DL is in opening position.

The conventional substation adopts the above-mentioned improvement plan, and the specific steps are as follows:

Step 1: When the line fails, the differential protection device 2 operates (pilot differential protection or other backup protection action), and the differential protection device 1 sends a "long jump signal" at the same time.

Step 2: The "remote jump signal" controls the action of the CJ2 contact in the differential protection device 1, disconnects 4DL, cuts off the small power supply (power plant), and at the same time sends a blocking and reclosing command to the protection device on the small power supply side.

Step 3: When the busbar of the substation loses power, the standby automatic switch operates correctly and reliably, disconnect 1DL, and close 2DL to ensure the safe operation of the substation.

The smart substation improvement scheme is shown in Figure 2. The smart protection device 1 is the local differential protection device, the smart protection device 2 is the small power supply side protection device, and the smart protection device 3 is the opposite side differential protection device. 1DL, 3DL, 4DL, 5DL, 6DL are in closing position, 2DL is in opening position.

The smart substation adopts the above-mentioned improvement scheme, and the specific steps are as follows:

Step 1: When the line fails, the intelligent protection device 3 acts (pilot differential protection or other backup protection action), and at the same time the intelligent protection device 1 sends a "long jump signal".

Step 2: The "remote jump signal" starts the intelligent protection device 1 to issue a trip command directly to the intelligent terminal on the side of the small power supply line through GOOSE point-to-point, and at the same time issue a blocking and reclosing command to the intelligent protection device 2 through the GOOSE network.

Step 3: When the busbar of the substation loses power, the standby automatic switch operates correctly and reliably, disconnect 1DL, and close 2DL to ensure the safe operation of the substation.

Claims (3)

1. a kind of band small power supply access system prepared auto restart application enhancements method, the system comprises the working powers as substation Circuit 1, the busbar I as system major network and busbar II and as spare circuit 2；When substation is connected to small power supply, Circuit 1, circuit 2 are connected by breaker 1DL and 2DL with system major network respectively, and small power supply passes through breaker 4DL and major network phase Even, breaker 4DL is in "on" position；Breaker 2DL is in hot stand-by duty；

It is characterized in that, circuit both sides protective device is all differential protection in the improved method；Small power supply is also equipped with phase The protective device answered；

The improved method is that substation, this side protective device sends " far jumping signal " by circuit offside protective device, is disconnected The breaker 4DL of small power supply is connected, and then ensures that prepared auto restart correctly acts；Simultaneously locking is sent out to the protective device of small power supply side Reclosing order, at this time breaker 1DL disconnections, 2DL are connected, and substation bus bar dead electricity, prepared auto restart correctly reliably acts.

2. a kind of band small power supply access system prepared auto restart application enhancements method according to claim 1, it is characterised in that：Institute State system be conventional substation when, specifically carry out as follows：

Step 1：When circuit 1 breaks down, when offside differential protection acts, while one is sent out to this side differential protection A " far jumping signal "；

Step 2：" far jumping signal " controls this side differential protection relay contact action, disconnects the open circuit of small power supply Device, while sending out lock-reclosing lock order to small power supply side protective device；

Step 3：Substation bus bar dead electricity, prepared auto restart correctly reliably act, and ensure substation safety operation.

3. a kind of band small power supply access system prepared auto restart application enhancements method according to claim 1, it is characterised in that：Institute State system be intelligent substation when, specifically carry out as follows：

Step 1：When circuit 1 breaks down, when offside intelligent protection device acts, while one is sent out to this side intelligent protection device A " far jumping signal "；

Step 2：It is point-to-point directly to small power supply line side intelligence by GOOSE that " far jumping signal " starts this side intelligent protection device Terminal sends out trip signal, while sending out lock-reclosing lock order to mains side protective device by GOOSE network；

Step 3：Substation bus bar dead electricity, prepared auto restart correctly reliably act, and ensure substation safety operation.