CN204947582U - Loop is distributed in the jumping of 220kV failure protection connection rationally - Google Patents

Abstract

220kV failure protection joint jump optimization configuration circuit, including: 1TJ main transformer protection 1, 2TJ main transformer protection 2, TJR bus differential protection, main transformer circuit breaker auxiliary protection, 2TJR bus differential protection 2, 220kV bus differential failure device, SLQD2 main transformer Circuit breaker auxiliary protection output contact, main transformer non-electrical device. The utility model is realized by adopting the three-side circuit of the main transformer when the high switch of the main transformer fails and trips the main transformer, which can effectively prevent the main transformer of the circuit breaker failure from being damaged due to the impact of the reverse short-circuit current of the 110kV system and the backup protection of the adjacent main transformer to reach the setting Value-based actions lead to the emergence of the problem of expanding the scope of accidents, shortening the time to remove faults and ensuring system safety.

Description

220kV failure protection joint trip optimization configuration circuit

technical field

The utility model belongs to the technical field of electric power, and in particular relates to an optimized configuration circuit for three sides of a 220kV main transformer that becomes high and fails in conjunction with jumping main transformers.

Background technique

Failure protection means that when the electrical equipment of 220kV and above fails, when the relay protection action issues a trip command and the circuit breaker refuses to operate, the failure of the circuit breaker is judged by using the protection action information of the faulty equipment and the current information of the circuit breaker that refuses to operate It can cut off other related circuit breakers in the same plant within a short time limit, so as to limit the scope of power outages to a minimum, thereby ensuring the stable operation of the entire power grid, and avoiding serious burning of faulty components such as generators and transformers and the collapse of the power grid. ACCIDENT. In modern high-voltage and extra-high-voltage power grids, failure protection has been widely used as a near-backup protection method.

For the main transformer connected to the double busbar wiring, there are the following situations in the failure behavior of the variable height circuit breaker:

1. When the main transformer fails internally, the protection of the main transformer will act, and the high-voltage circuit breaker will fail. At this time, the main transformer protection action trips the other side circuit breakers except the failure circuit breaker. The circuit breaker failure protection needs to trip all the power supply branches on the bus where the transformer is located to remove the fault.

2. If the high-voltage side system fails, the backup protection of the transformer trips the high-voltage side circuit breaker, and the high-voltage side circuit breaker fails. The circuit breaker failure protection needs to trip all the power supply branches on the high-voltage side busbar and other side circuit breakers of the main transformer to eliminate the fault.

3. When the busbar is faulty and the variable height circuit breaker fails, the bus differential protection jumps off other active branches on the busbar where the main transformer is located, but the power supply on the other side of the main transformer will continue to provide short-circuit current to the faulty busbar. If the main transformer is still relied on for backup If the protection band has a certain delay to trip the three-side switch to remove the fault, the transformer may be burned. The power circuit breaker on the other side of the main transformer must be tripped in the way of failure joint trip to remove the fault.

Through the above analysis, it can be concluded that when the bus differential protection and failure protection cooperate, no matter whether the main transformer protection action or the bus differential protection action, the circuit breaker failure protection should be activated. When the main transformer circuit breaker has indeed failed, the circuit breaker failure On the one hand, the protection operates to trip all power supply branches of the bus where the main transformer circuit breaker is located, and on the other hand, it operates to jointly trip the power circuit breakers on other sides of the main transformer.

However, in actual engineering, due to the differences in the realization of bus differential protection and main transformer protection functions, the start-up, logic discrimination and exit circuit design of the failure circuit are various. For example, the journal document "On Main Transformer 220kV Side Switch Failure to Trip Main Transformer Three-side Switch" adopts the failure joint tripping scheme based on whether the proprietary device fails to start and release the high-voltage blocking; "Transformer circuit breaker failure protection device releases the voltage blocking Selection of the plan>The functions of protection action judgment, failure current criterion and delay exit are implemented in the 220kV bus differential protection, etc.

In 220kV substations and 500kV substations, there are many secondary equipment configurations in circuit breaker protection, and multiple screen cabinets need to be equipped, which requires a large investment and covers a large area. How to optimize the configuration of failure protection and reduce the configuration of secondary equipment and the number of screen cabinets is of positive significance for saving construction investment, reducing the area occupied by the district, and speeding up the construction period.

Contents of the invention

In order to solve the above-mentioned problems, the utility model provides a 220kV failure protection tripping optimization configuration circuit, which uses the circuit breaker of the main transformer protection screen to assist in protecting the circuit breakers on each side of the outlet tripping main transformer.

The technical scheme of the utility model is as follows:

220kV failure protection joint jump optimization configuration circuit, including: 1TJ main transformer protection 1, 2TJ main transformer protection 2, TJR bus differential protection, main transformer circuit breaker auxiliary protection, 2TJR bus differential protection 2, 220kV bus differential failure device, SLQD2 main transformer Circuit breaker auxiliary protection output contact, main transformer non-electricity device; among them, 1TJ main transformer protection 1, 2TJ main transformer protection 2, TJR bus differential protection connected to main transformer circuit breaker auxiliary protection starting failure switch input; 2TJ main transformer protection 2, 2TJR bus differential protection 2 is connected to 220kV bus differential failure device start-up failure switch-in; 1TJ main transformer protection 1, 2TJ main transformer protection 2, TJR bus differential protection connected to main transformer non-electricity device starts non-electricity trip, and main transformer circuit breaker After the auxiliary protection device receives the starting failure of the action contact, the output contact SLQD2, SLQD2 is the auxiliary protection output contact of the main transformer circuit breaker, which includes the protection action (that is, the starting failure has a switch input) and the condition of flow, and is connected in series with the protection action contact It is connected to the tripping input circuit of the non-electricity protection of the transformer to complete the function of tripping each side of the main transformer when the main transformer becomes high and fails.

When the auxiliary protection device of the circuit breaker of the main transformer only realizes the function of each side of the joint tripping, it is required to use the protection action contact to switch to the auxiliary protection device of the circuit breaker, and the current discrimination contact in the circuit of each side of the main transformer of the joint tripping main transformer is connected in series with the protection action contact. The failure action delay starts the main transformer non-electricity trip circuit and trips the circuit breakers on each side of the main transformer.

Action principle: When 1TJ main transformer protection 1 or 2TJ main transformer protection 2 or TJR bus differential protection operates, the starting bus protection device fails and the failure judgment is completed. At the same time, after the auxiliary protection device of the main transformer circuit breaker receives the start failure of the action contact, the output contact SLQD2 is connected in series with the protection action contact to the trip input circuit of the non-electrical protection of the transformer, and completes the function of tripping each side of the main transformer when the main transformer fails. .

In order to prevent the circuit breakers on each side of the transformer from being accidentally tripped when the transformer circuit breaker is not in failure, the outlet can be tripped after a short delay. At the same time, increasing the delay can also prevent instantaneous interference from causing the circuit breakers on each side of the transformer to be accidentally tripped. The delay should be longer than the tripping of the circuit breaker. The sum of time and return time of bus differential protection, preferably 100ms.

In order to improve the sensitivity of the failure protection device, when the transformer protection device fails to start, the current discrimination element composed of phase current, zero sequence current and negative sequence current OR gate is used to start the failure protection device. When the circuit breaker trips, the current discrimination element is required to return quickly. In the early stage, the circuit breaker failure criterion of the protection device was the phase current start-up. In order to ensure the sensitivity, the current setting value was generally small, and the setting value was about 20% of the rated current. During normal operation, the current discrimination relay is in the action state and does not play a blocking role, which reduces the reliability of failure protection. However, the zero-sequence and negative-sequence currents only exist when there is a fault, and the criterion of "zero-sequence or negative-sequence current" will not start during normal operation. For transformer faults, most of which are asymmetric faults, such as inter-turn short circuit, single-phase grounding, etc., the criterion of "zero-sequence or negative-sequence current" can be effectively discriminated. When there is a three-phase short circuit or a three-phase symmetrical ground short circuit, there is no zero-sequence and negative-sequence current, and the action depends on the "phase current" criterion. Due to the addition of the "zero-sequence or negative-sequence current" criterion, the starting value of the "phase current" can be increased to 1.2 times the rated current, and it will not start under normal operating conditions, which can improve the reliability of failure protection.

Compared with the prior art, the utility model has the following advantages and beneficial effects:

1. When the high switch of the main transformer needs to be tripped but fails, if the backup protection is still used to cut off the switches on each side of the main transformer with a certain delay, there may be two consequences: one is that the main transformer of the circuit breaker failure is affected by the 110kV system Second, the backup protection of the adjacent main transformer reaches the set value and operates, resulting in the expansion of the scope of the accident. The utility model adopts the realization of the three-side circuit of the main transformer variable height switch failure joint jumping main transformer, which can effectively avoid the occurrence of the above problems, shorten the fault removal time, and ensure the safety of the system.

2. Compared with the prior art, the utility model greatly simplifies the equipment configuration and reduces the number of screen cabinets.

Description of drawings

Figure 1a is the wiring diagram of the main transformer circuit breaker auxiliary protection switch input;

Figure 1b is the wiring diagram of the starting failure circuit;

Figure 1c is the outlet circuit wiring diagram;

Fig. 2 is a structural schematic diagram of a failure current judging element adopted in the present invention.

detailed description

The technical solution of the utility model will be clearly and completely described below in conjunction with the accompanying drawings.

The utility model 220kV failure protection joint jump optimization configuration circuit includes: 1TJ main transformer protection 1, 2TJ main transformer protection 2, TJR bus differential protection, main transformer circuit breaker auxiliary protection, 2TJR bus differential protection 2, 220kV bus differential failure device, SLQD2 main transformer circuit breaker auxiliary protection output contact, main transformer non-electricity device.

As shown in Figure 1a, 1TJ main transformer protection 1, 2TJ main transformer protection 2, and TJR bus differential protection are connected to the main transformer circuit breaker auxiliary protection start failure switch; as shown in Figure 1b, 2TJ main transformer protection 2, 2TJR bus differential protection Protection 2 is connected to the 220kV bus differential failure device start failure switch; as shown in Figure 1c, 1TJ main transformer protection 1, 2TJ main transformer protection 2, and TJR bus differential protection connected to the main transformer non-electricity device start non-electricity trip, and the main After the auxiliary protection device of the transformer circuit breaker receives the starting failure of the action contact, the output contact SLQD2, SLQD2 is the output contact of the auxiliary protection of the main transformer circuit breaker, including the protection action (that is, the condition of starting failure and current flow), and the protection action The contacts are connected in series to the tripping input circuit of the non-electrical protection of the transformer to complete the function of tripping each side of the main transformer when the main transformer becomes high and fails.

When the auxiliary protection device of the circuit breaker of the main transformer only realizes the function of each side of the joint tripping, it is required to use the protection action contact to switch to the auxiliary protection device of the circuit breaker, and the current discrimination contact in the circuit of each side of the main transformer of the joint tripping main transformer is connected in series with the protection action contact. The failure action delay starts the main transformer non-electricity trip circuit and trips the circuit breakers on each side of the main transformer.

Action principle: When 1TJ main transformer protection 1 or 2TJ main transformer protection 2 or TJR bus differential protection operates, the starting bus protection device fails and the failure judgment is completed. At the same time, after the auxiliary protection device of the main transformer circuit breaker receives the start failure of the action contact, the output contact SLQD2 is connected in series with the protection action contact to the trip input circuit of the non-electrical protection of the transformer, and completes the function of tripping each side of the main transformer when the main transformer fails. .

In order to prevent the circuit breakers on each side of the transformer from being accidentally tripped when the transformer circuit breaker is not in failure, the outlet can be tripped after a short delay. At the same time, increasing the delay can also prevent instantaneous interference from causing the circuit breakers on each side of the transformer to be accidentally tripped. The delay should be longer than the tripping of the circuit breaker. The sum of time and return time of bus differential protection, preferably 100ms.

As shown in Figure 2, in order to improve the sensitivity of the failure protection device, when the transformer protection device fails to start, the current discrimination element composed of phase current, zero sequence current and negative sequence current or gate is used to start the failure protection device. When the circuit breaker trips, the current discrimination element is required to return quickly. In the early stage, the circuit breaker failure criterion of the protection device was the phase current start-up. In order to ensure the sensitivity, the current setting value was generally small, and the setting value was about 20% of the rated current. During normal operation, the current discrimination relay is in the action state and does not play a blocking role, which reduces the reliability of failure protection. However, the zero-sequence and negative-sequence currents only exist when there is a fault, and the criterion of "zero-sequence or negative-sequence current" will not start during normal operation. For transformer faults, most of which are asymmetrical faults, such as inter-turn short circuit, single-phase grounding, etc., the criterion of "zero-sequence or negative-sequence current" can be effectively discriminated. When there is a three-phase short circuit or a three-phase symmetrical ground short circuit, there is no zero-sequence and negative-sequence current, and at this time it depends on the "phase current" criterion to act. Due to the addition of the "zero-sequence or negative-sequence current" criterion, the starting value of the "phase current" can be increased to 1.2 times the rated current, and it will not start under normal operating conditions, which can improve the reliability of failure protection.

In order to prevent a single failure of the device from causing failure or tripping of the main transformer protection action, the following two points should be achieved during specific implementation:

1. While the protection action contact is connected to the auxiliary protection device of the circuit breaker, at the same time, the current discrimination contact is connected in series with the protection action contact in the circuit on each side of the corresponding failure start, reset voltage, and joint trip main transformer.

2. In the case of a limited number of protective action contacts, the priority of the protective action contacts should be considered in the following order: the protective action contacts are connected to the auxiliary protection device of the circuit breaker, the protective action contacts are connected in series in the failure start circuit, and the connection Jump the series connection protection action contacts of the circuits on each side, and release the series connection protection action contacts of the complex pressure blocking circuit.

Claims (1)

1. Loop is distributed in the jumping of 1.220kV failure protection connection rationally, it is characterized in that, comprising: 1TJ main transformer protection 1,2TJ main transformer protection 2, TJR bus differential protection, main transformer circuit breaker auxiliary protection, 2TJR bus differential protection 2,220kV mother difference malfunctioning device, SLQD2 main transformer circuit breaker auxiliary protection output contact, main transformer non-charge device; Wherein, 1TJ main transformer protection 1,2TJ main transformer protection 2, the conk-out of TJR bus differential protection access main transformer circuit breaker auxiliary protection open into; 2TJ main transformer protection 2,2TJR bus differential protection 2 access the malfunctioning device conk-out of 220kV mother difference open into; 1TJ main transformer protection 1,2TJ main transformer protection 2, TJR bus differential protection access main transformer non-charge device starts non electrical quantity tripping operation; after main transformer circuit breaker auxiliary protection device receives action connection point conk-out simultaneously; output contact SLQD2; connect with protection act contact and access the tripping operation input circuit that transformer non-electricity protects, complete the function that main transformer uprises the malfunctioning jumping each side of main transformer.