CN211720258U - Transformer heavy gas protection external trip circuit - Google Patents

Abstract

The utility model discloses an external trip circuit for heavy gas protection of a transformer. In the circuit, one end of a normally open contact of a protection trip outlet relay is connected to a positive pole of a DC power supply, the other end is connected to one end of a protection trip pressure plate, and the other end of the protection trip pressure plate is connected to the other end of the protection trip pressure plate. One end is connected to one end of the auxiliary normally open contact of the circuit breaker, the other end of the auxiliary normally open contact of the circuit breaker is connected to one end of the opening coil, and the other end of the opening coil is connected to the negative pole of the DC power supply; the gas relay is installed in the transformer body oil tank and On the pipeline of the oil pillow, when there is an internal fault in the transformer, the contact of the heavy gas relay is closed; one end of the contact of the heavy gas relay is connected to the positive pole of the DC power supply, and the other end is connected to the other end of the protection tripping pressure plate. The transformer of the utility model protects the external trip circuit of heavy gas. When the user-side transformer has an internal fault, the upper-level power grid circuit breaker trips to cut off the power supply of the transformer, thereby avoiding the expansion of the accident scope and improving the safety and reliability of the power supply system.

Description

Transformer heavy gas protection external trip circuit

technical field

The utility model relates to the technical field of transformer protection and control, in particular to an external trip circuit for heavy gas protection of a transformer.

Background technique

Transformer is an important electrical equipment in the power system. Under normal circumstances, it can convert AC power of one voltage and current into another kind of AC power of the same frequency and current, so as to provide power with suitable voltage level for consumers. . The gas protection is the main protection for the internal fault of the transformer, which can effectively reflect the internal fault of the transformer. Gas protection includes light gas protection and heavy gas protection. The light gas protection acts on the signal, and the heavy gas acts on the tripping. In the prior art, the contact point of the transformer gas relay is connected to the relay protection device through the DC power supply. When a fault such as a short circuit occurs inside the transformer, the normally open contact of the transformer heavy gas relay is connected, and the transformer heavy gas protection circuit is connected. The circuit breakers on both high and low voltage sides of the transformer are tripped to cut off the power supply of the transformer to prevent the scope of the accident from expanding. The regulations stipulate that oil-immersed transformers above 800kVA need to be equipped with gas protection, but some small-scale substations or power distribution rooms are not equipped with DC power supplies or protection devices. The transformer cannot cut off the power supply, which further aggravates the fault of the transformer, expands the scope of the accident, and affects the safety and reliability of the power supply system.

Utility model content

In order to solve the technical problems existing in the above-mentioned prior art, the utility model provides an external trip circuit for heavy gas protection of a transformer. The specific technical solutions are as follows:

An external trip circuit for heavy gas protection of a transformer, comprising: a DC power supply, a normally open contact of a protection trip outlet relay, a protection trip pressure plate, an auxiliary normally open contact of a circuit breaker, a trip coil, a gas relay and a contact of the heavy gas relay; the protection tripping One end of the normally open contact of the outlet relay is connected to the positive pole of the DC power supply, the other end is connected to one end of the protection tripping pressure plate, and the other end of the protection tripping pressure plate is connected to one end of the auxiliary normally open contact of the circuit breaker, so The other end of the auxiliary normally open contact of the circuit breaker is connected to one end of the opening coil, and the other end of the opening coil is connected to the negative pole of the DC power supply; the gas relay is installed on the main body oil tank of the user-side transformer and On the pipeline of the oil pillow, it is used to close the contact of the heavy gas relay when the transformer fails; one end of the contact of the heavy gas relay is connected to the positive pole of the DC power supply, and the other end is connected to the other end of the protection tripping pressure plate connection; the auxiliary normally open contact of the circuit breaker is in a closed state when the circuit breaker is closed, and the normally open contact of the protection tripping outlet relay is closed when a short circuit fault occurs in external lines and equipment.

In a possible design, the circuit further includes a trip holding relay coil and its self-holding contact; the trip holding relay coil is connected in series between the protection trip pressure plate and the auxiliary normally open contact of the circuit breaker; the One end of the self-holding contact of the trip holding relay is connected to the positive pole of the DC power supply, and the other end is connected to the common terminal of the protection tripping pressure plate and the coil of the trip holding relay.

In a possible design, the contact point of the heavy gas relay is wired to the control wiring terminal block in the switch cabinet of the feeder line of the upper-level substation.

In a possible design, the protection trip outlet relay normally open contact, the protection trip pressure plate, the circuit breaker auxiliary normally open contact, the opening coil, the trip hold relay coil, the trip hold The relay self-holding contacts belong to the internal components of the microcomputer protection measurement and control device, and the heavy gas relay contacts are wired to the internal circuit of the microcomputer protection measurement and control device through the control wiring terminal row.

In a possible design, the microcomputer protection measurement and control device is connected to the background monitoring computer through a communication cable, and is used to feed back the action of the heavy gas relay contact to the background monitoring computer.

In a possible design, the background monitoring microcomputer sends out a trip alarm message when the contact of the heavy gas relay is closed.

In a possible design, a DC circuit breaker is provided at the DC power supply.

In one possible design, the voltage of the DC power supply is 220V.

The main advantages of the technical solution of the present utility model are as follows:

The transformer heavy gas protection trip circuit of the utility model, by setting the gas relay and the heavy gas relay contact, when the user-side transformer has internal faults (such as inter-turn and inter-layer short circuit, iron core fault, bushing internal fault, winding internal disconnection) In case of faults such as insulation deterioration and oil level drop), the contact of the heavy gas relay is closed, and the control circuit of the grid circuit breaker of the upper substation is connected, the opening coil is energized, the circuit breaker protection trips, and the power supply of the transformer is cut off to avoid the scope of the accident. Further expand and improve the safety and reliability of the power supply system. In addition, the original protection circuit of the power grid circuit breaker of the upper-level substation is used, the existing resources are fully utilized, the structure is simplified, and the degree of integration is high.

Description of drawings

The accompanying drawings described here are used to provide a further understanding of the embodiments of the present utility model and constitute a part of the present utility model. The schematic embodiments of the present utility model and descriptions thereof are used to explain the present utility model and do not constitute Improperly limited. In the attached image:

FIG. 1 is an external trip circuit for heavy gas protection of a transformer provided by an embodiment of the present invention.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the specific embodiments of the present invention and the corresponding drawings. Obviously, the described embodiments are only some of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present invention.

The technical solutions provided by the embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

The embodiment of the present utility model provides an external trip circuit for heavy gas protection of a transformer, as shown in FIG. 1 , including: a DC power supply KM, a normally open contact BTJ of a protection trip outlet relay, a protection trip pressure plate LP1, and an auxiliary normally open contact of a circuit breaker QF, opening coil TQ, gas relay and heavy gas relay contact WSJ; one end of the normally open contact BTJ of the protection tripping outlet relay is connected to the positive pole +KM of the DC power supply, and the other end is connected to one end of the protection tripping pressure plate LP1, the protection tripping pressure plate LP1 The other end of the circuit breaker is connected to one end of the auxiliary normally open contact QF of the circuit breaker, the other end of the auxiliary normally open contact QF of the circuit breaker is connected to one end of the opening coil TQ, and the other end of the opening coil TQ is connected to the negative pole of the DC power supply -KM; The Buchholz relay is installed on the main body oil tank of the user-side transformer and the pipeline of the oil pillow, which is used to close the heavy gas relay contact WSJ when the transformer fails; one end of the heavy gas relay contact WSJ is connected to the positive pole +KM of the DC power supply, and the other end is connected. It is connected to the other end of the protection trip platen LP1; the auxiliary normally open contact QF of the circuit breaker is in a closed state when the circuit breaker is closed, and the normally open contact BTJ of the protection trip outlet relay is closed when a short circuit fault occurs in the external line and equipment.

The working principle of the transformer heavy gas protection external trip circuit provided by the embodiment of the present utility model is described below:

In this circuit, the DC power supply KM, the normally open contact BTJ of the protection trip outlet relay, the protection trip pressure plate LP1, the auxiliary normally open contact QF of the circuit breaker and the opening coil TQ constitute the circuit breaker protection trip circuit. When the circuit breaker is closed, the auxiliary normally open contact QF of the circuit breaker is in a closed state. When the external line or equipment is short-circuited, the normally open contact BTJ of the protection tripping outlet relay is closed, so that the circuit where the protection tripping outlet relay normally open contact BTJ, the protection tripping pressure plate LP1, the auxiliary normally open contact QF of the circuit breaker and the opening coil TQ are located is connected to the DC. The power supply KM is connected, the opening coil TQ is energized, and the operating mechanism is driven to complete the circuit breaker protection trip. On the basis of the protection trip circuit, the user side transformer heavy gas relay contact WSJ contact is wired to the circuit breaker protection trip circuit. In this way, when an internal fault occurs in the transformer, the heavy gas relay contact WSJ of the gas relay is closed, the heavy gas relay contact WSJ, the auxiliary normally open contact QF of the circuit breaker and the opening coil TQ are connected to the DC power supply KM circuit, and the opening coil TQ is obtained. electricity, the circuit breaker protection trips, and the transformer is cut off. The protection trip pressure plate LP1 can be closed or opened under human control, which is convenient to control whether the protection trip circuit in the circuit is put into use.

It can be seen that the transformer heavy gas protection trip circuit provided by the embodiment of the present utility model, by setting the gas relay and the heavy gas relay contact WSJ, when the user-side transformer has an internal fault (such as inter-turn and inter-layer short circuit, iron core fault, bushing internal fault) In the event of fault, internal winding breakage, insulation deterioration and oil level drop, etc.), the heavy gas relay contact WSJ is closed, the opening coil TQ is energized, the circuit breaker is tripped, and the power supply of the transformer is cut off to avoid further expansion of the scope of the accident and improve the power supply system. Safety and reliability. In addition, the original protection circuit of the circuit breaker is used, the existing resources are fully utilized, the structure is simplified, and the degree of integration is high.

Further, the transformer heavy gas protection external trip circuit provided by the embodiment of the present invention also includes a trip holding relay coil TBJ and its self-holding contact; the trip holding relay coil TBJ is connected in series between the protection trip pressure plate LP1 and the auxiliary normally open contact QF of the circuit breaker. One end of the self-holding contact TBJ1 of the trip holding relay is connected to the positive pole +KM of the DC power supply, and the other end is connected to the protection trip pressure plate LP1 and the common terminal of the trip holding relay coil TBJ. In this way, on the one hand, when the coil TBJ of the trip holding relay is energized, the self-holding contact TBJ1 of the trip holding relay is closed, which can prevent the opening contact during the normal opening operation from being tripped due to short ON time or too fast return or short circuit accident. The normally open contact BTJ of the trip outlet relay is jittering and the closing may be insufficient, which may cause the opening coil TQ to fail to act correctly and reliably. On the other hand, after the heavy gas relay contact WSJ is closed, when the trip holding relay coil TBJ is energized, the trip holding relay self-holding contact TBJ1 is closed to ensure that the trip coil TQ is fully energized before the circuit breaker trips. Through the self-holding contact TBJ1 of the trip holding relay, the opening coil TQ is connected to the DC power supply KM, which improves the reliability of the normal opening and protection tripping of the circuit breaker.

In the embodiment of the present invention, the heavy gas relay contact WSJ is wired to the control wiring terminal block in the switch cabinet of the feeder line of the substation. Specifically, the normally open contact BTJ of the protection trip outlet relay, the protection trip pressure plate LP1, the auxiliary normally open contact QF of the circuit breaker, the opening coil TQ, the trip holding relay coil TBJ, and the self-holding contact TBJ1 of the trip holding relay all belong to the inside of the microcomputer protection measurement and control device. Components, heavy gas relay contact WSJ is wired to the internal circuit of the microcomputer protection measurement and control device through the control terminal block. As shown in Figure 1, the terminal numbers of the control wiring terminal row in the switch cabinet of the feed-out line are I/93 and I/94, which are then wired to the terminals 1nB4 and 1nB5 of the microcomputer protection measurement and control device of the cabinet respectively through the wires. 1nB4, 1nB5 is a pair of protection action passive empty output contacts of the microcomputer protection measurement and control device. And 1nB4 and 1nC3, 1nB5 and 1nC8 respectively realize electrical connection inside the microcomputer protection measurement and control device.

Generally, the distance between the user-side transformer and the power grid of the upper-level substation is generally not too far. The control cable between the heavy gas relay contact WSJ and the switch cabinet of the power grid feeder of the upper substation can be laid in the cable trench. For example, it can be laid in the same cable trench as the high-voltage power supply cable and effectively isolated.

Further, in order to facilitate monitoring the action of heavy gas protection of the transformer, the microcomputer protection measurement and control device is connected to the background monitoring microcomputer through a communication cable, and is used to feed back the action information of the heavy gas relay contact WSJ to the background monitoring microcomputer. An alarm message is issued when the contact WSJ is closed. In the background monitoring computer, the name and number of the protection information of "heavy gas protection action" are defined respectively. The alarm signal on the monitoring computer in the background can be set to light alarm, sound alarm or sound and light alarm. For the convenience of reminding the background staff, the displayed subtitles can appear in a flashing manner.

Further, the microcomputer protection measurement and control device is connected to the background monitoring microcomputer with a communication management machine, through which the information collected from each microcomputer protection measurement and control device can be collected and processed, and then communicated and transmitted to the background monitoring microcomputer. Realize the online display and alarm of the alarm information of "transformer heavy gas protection fault" on the background monitoring computer.

Further, in the external trip circuit of the transformer heavy gas protection provided by the embodiment of the present invention, a DC circuit breaker 1DK is arranged at the DC power supply KM, which is convenient to control whether the DC power supply KM supplies power normally.

Optionally, the voltage of the DC power source KM may be 220V.

To sum up, the external trip circuit of the transformer heavy gas protection provided by the embodiment of the present utility model is connected by connecting the user-side transformer heavy gas relay contact WSJ contact to the control wiring terminal block in the switch cabinet of the feeder line of the upper-level substation, and finally wiring. to the internal circuit of the microcomputer protection measurement and control device of the cabinet. In this way, when an internal fault occurs in the transformer, the heavy gas relay contact WSJ of the gas relay is closed, the heavy gas relay contact WSJ, the trip holding relay coil TBJ, the circuit breaker auxiliary normally open contact QF and the opening coil TQ are connected to the DC power supply KM circuit. , The opening coil TQ is energized, the circuit breaker protection tripping, cutting off the power supply of the transformer, avoiding the further expansion of the scope of the accident, and improving the safety and reliability of the power supply system. Utilize the original protection circuit of the power grid circuit breaker in the upper-level substation, make full use of the existing resources, simplify the structure, and have a high degree of integration. And through the background monitoring microcomputer, fault information can be obtained in time.

It should be noted that, in this document, relational terms such as "first" and "second" etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply these There is no such actual relationship or sequence between entities or operations. Moreover, the terms "comprising", "comprising" or any other variation thereof are intended to encompass a non-exclusive inclusion such that a process, method, article or device that includes a list of elements includes not only those elements, but also includes not explicitly listed or other elements inherent to such a process, method, article or apparatus. In addition, "front", "rear", "left", "right", "upper" and "lower" in this document are all referred to the placement state shown in the accompanying drawings.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present utility model, but not to limit them; although the present utility model has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: It is still possible to modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements to some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions depart from the spirit of the technical solutions of the embodiments of the present invention and range.

Claims (8)

1. A transformer heavy gas protection external trip circuit is characterized in that, comprising: DC power supply, protection trip outlet relay normally open contact, protection trip pressure plate, circuit breaker auxiliary normally open contact, opening coil, gas relay and heavy gas relay contact; One end of the normally open contact of the protection trip outlet relay is connected to the positive pole of the DC power supply, the other end is connected to one end of the protection trip pressure plate, and the other end of the protection trip pressure plate is connected to the auxiliary normally open contact of the circuit breaker. one end is connected, the other end of the auxiliary normally open contact of the circuit breaker is connected with one end of the opening coil, and the other end of the opening coil is connected with the negative electrode of the DC power supply; The gas relay is installed on the main body oil tank of the user-side transformer and the pipeline of the oil pillow, and is used to close the contact of the heavy gas relay when the transformer fails; One end of the heavy gas relay contact is connected to the positive pole of the DC power supply, and the other end is connected to the other end of the protection tripping pressure plate; The auxiliary normally open contact of the circuit breaker is in a closed state when the circuit breaker is in a working state, and the normally open contact of the protection tripping outlet relay is closed when a short-circuit fault occurs in external lines and equipment. 2. The transformer heavy-gas protection external trip circuit according to claim 1, wherein the circuit further comprises a trip holding relay coil and a self-holding contact thereof; the trip holding relay coil is connected in series between the protection trip pressing plate and the auxiliary normally open contact of the circuit breaker; One end of the self-maintaining contact of the trip holding relay is connected to the positive pole of the DC power supply, and the other end is connected to the common terminal of the protection tripping pressure plate and the coil of the trip holding relay. 3 . The external trip circuit for heavy gas protection of a transformer according to claim 2 , wherein the contact point of the heavy gas relay is wired to the control wiring terminal block in the switch cabinet of the outgoing line of the substation. 4 . 4 . The external trip circuit for heavy gas protection of a transformer according to claim 3 , wherein the protection trip outlet relay normally open contact, the protection trip pressure plate, the circuit breaker auxiliary normally open contact, the opening The coil, the trip holding relay coil, and the self-holding contact of the trip holding relay belong to the internal components of the microcomputer protection measurement and control device, and the heavy gas relay contact is wired to the internal circuit of the microcomputer protection measurement and control device through the control terminal block. middle. 5 . The external trip circuit for transformer heavy gas protection according to claim 4 , wherein the microcomputer protection measurement and control device is connected to a background monitoring microcomputer through a communication cable, and is used to feed back the heavy gas to the background monitoring microcomputer. 6 . Action of the relay contacts. 6 . The external trip circuit for transformer heavy gas protection according to claim 5 , wherein the background monitoring microcomputer sends out a trip alarm message when the heavy gas relay contacts are closed. 7 . 7 . The external trip circuit for heavy gas protection of a transformer according to claim 1 , wherein a DC circuit breaker is provided at the DC power supply. 8 . 8 . The external trip circuit for heavy gas protection of a transformer according to claim 1 , wherein the voltage of the DC power supply is 220V. 9 .

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