CN204886155U - Malfunctioning protection of 220kV allies oneself with jumps optimal configuration return circuit - Google Patents

Abstract

A 220kV failure protection joint jump optimization configuration circuit, including: 1TJ main transformer protection 1, 2TJ main transformer protection 2, TJR bus difference protection, main transformer circuit breaker auxiliary protection, contact SLQD1, 220kV bus difference failure device, 220kV bus difference failure The device is connected to the three-side outlet contact, and the main transformer is a non-electric device. The utility model adopts the three-side circuit of the main transformer with joint tripping, which can effectively prevent the main transformer of circuit breaker failure from being damaged due to the impact of the reverse short-circuit current of the 110kV system and the action of the backup protection of the adjacent main transformer reaching the set value, resulting in enlarged accidents The emergence of the range problem shortens the time to remove the fault and ensures the safety of the system.

Description

A 220kV Failure Protection Interconnection Optimal 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 and trips the three sides of the main transformer.

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 protection action information of the faulty equipment and the current information of the circuit breaker that refuses to operate are used to constitute the protection against the failure of the circuit breaker. Discrimination, other related circuit breakers in the same plant can be cut off in a short time limit, so that the scope of power failure can be limited to the minimum, so as to ensure the stable operation of the entire power grid, and avoid serious burning of faulty components such as generators and transformers and the collapse of the power grid disintegrate 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 circuit breaker optimized configuration circuit, using the failure protection outlet of the 220kV bus differential failure protection device to trip the circuit breakers on each side of the main transformer.

The technical scheme of the utility model is as follows:

A 220kV failure protection joint jump optimization configuration circuit, including: 1TJ main transformer protection 1, 2TJ main transformer protection 2, TJR bus difference protection, main transformer circuit breaker auxiliary protection, contact SLQD1, 220kV bus difference failure device, 220kV bus difference failure Device joint trip three-side outlet 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-in; 1TJ main transformer protection 1 , 2TJ main transformer protection 2, TJR bus differential protection connected to 220kV bus differential failure device start failure switch in, at the same time the output contact SLQD1 and the protection action contact start the 220kV bus differential failure device in series; Connect to the non-electricity device of the main transformer to start the non-electricity trip.

Action principle: When 1TJ main transformer protection 1 or 2TJ main transformer protection 2 or TJR bus differential protection operates, the auxiliary protection device of the main transformer circuit breaker receives the activation contact failure, and completes the failure judgment according to the current criterion, the output contact SLQD1 and the protection The actuating contacts start the 220kV bus differential failure device in series, and then the contacts of the 220kV bus differential failure device are connected to the trip 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 fails. The contact SLQD1 is the auxiliary protection output contact of the main transformer circuit breaker, including the protection action (that is, the starting failure has a switch input) and the conditions of current flow.

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 also used to start the failure protection device.

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 a 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 ways

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

The utility model is a 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, contact SLQD1, 220kV bus differential failure device, 220kV The bus differential failure device is composed of the three-side outlet contact and the main transformer non-electrical 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, 1TJ main transformer protection 1, 2TJ main transformer Protection 2. The TJR bus differential protection is connected to the 220kV bus differential failure device to start the failure switch, and at the same time the output contact SLQD1 and the protection action contact are connected in series to start the 220kV bus differential failure device; as shown in Figure 1c, the 220kV bus differential failure device trips three sides The outlet contact is connected to the non-electricity device of the main transformer to start the non-electricity trip.

Action principle: When 1TJ main transformer protection 1 or 2TJ main transformer protection 2 or TJR bus differential protection operates, the auxiliary protection device of the main transformer circuit breaker receives the activation contact failure, and completes the failure judgment according to the current criterion, the output contact SLQD1 and the protection The action contact starts the 220kV bus differential failure device in series, as shown in Figure 1a and Figure 1b, and then the contact of the 220kV bus differential failure device is connected to the trip input circuit of the transformer non-electricity protection, and the main transformer is completed. The function of each side is shown in Fig. 1c. The contact SLQD1 is the auxiliary protection output contact of the main transformer circuit breaker, including the protection action (that is, the starting failure has a switch input) and the conditions of current flow.

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 fault of the device from causing failure or tripping of the main transformer protection action, the following two points should be done during the specific implementation process:

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 220kV failure protection connection jumping 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, contact SLQD1,220kV mother difference malfunctioning device, 220kV mother difference malfunctioning device connection jumping three side outlet 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; The malfunctioning device conk-out of 1TJ main transformer protection 1,2TJ main transformer protection 2, TJR bus differential protection access 220kV mother difference open into, output contact SLQD1 connect with protection act contact and starts the female poor malfunctioning device of 220kV simultaneously; 220kV mother difference malfunctioning device connection jumping three side outlet contact access main transformer non-charge device starts non electrical quantity tripping operation.