CN212969041U - Novel over-temperature tripping loop for dry-type transformer - Google Patents

Abstract

The utility model relates to a novel overtemperature tripping circuit for a dry type transformer, which comprises a temperature rise detection module, a three-phase two-out module and an overtemperature tripping module, wherein the temperature rise detection module comprises a three-phase temperature relay respectively connected with A, B, C phase winding PCT thermistors of the dry type transformer and intermediate relays K1, K2 and K3 respectively connected with the three-phase temperature relay; the two-out-of-three module comprises an input end and an output end, wherein the input end is composed of three groups of series loops consisting of K1 and K2, K2 and K3, and K3 and K1, and the output end is composed of the three groups of series loops in parallel; the input end of the over-temperature tripping module and the output end of the two-out-of-three module are connected with the over-temperature tripping contact in series to form an AND gate circuit; and the output end of the over-temperature tripping module is connected with the non-electrical quantity protection input end of the dry-type transformer comprehensive protection device. The utility model discloses can eliminate current dry-type transformer excess temperature tripping circuit and adopt single contact tripping operation, the poor potential safety hazard of protection reliability.

Description

Novel over-temperature tripping loop for dry-type transformer

Technical Field

The utility model belongs to the technical field of the transformer protection circuit, especially, relate to a dry-type transformer is with novel excess temperature tripping circuit.

Background

In order to increase capacity, the dry-type transformer applied in power system enterprises mostly adopts a forced air cooling (AF) mode, and in order to ensure safe and stable operation of the dry-type transformer, higher requirements are provided for the operation temperature monitoring, alarming and tripping functions of the dry-type transformer, so that the performance of the dry-type temperature-variable controller and the design of a secondary loop thereof are particularly important.

The overtemperature alarm and trip control loop of the existing dry-type transformer is generally designed as follows:

1) overtemperature alarm circuit: when the temperature of the dry-type transformer rises to reach an alarm set value, the temperature controller 'over-temperature alarm' contact of the dry-type transformer acts, the 'over-temperature alarm' contact is uploaded to the thermal control DCS system or the integrated automation background, and the thermal control DCS system or the integrated automation background displays the over-temperature alarm in a light character alarm mode to inform an operator on duty to adjust the system operation mode in time or perform manual intervention.

2) An over-temperature tripping loop: when the temperature of the dry type transformer continuously rises to reach a tripping set value, a temperature controller 'over-temperature tripping' contact of the dry type transformer acts, the 'over-temperature tripping' contact is usually connected into a transformer comprehensive protection device, and the transformer comprehensive protection device sends out a tripping instruction to drive the high-voltage side circuit breaker and the low-voltage side circuit breaker of the dry type transformer to be switched off, or is directly connected in parallel with a tripping control loop of the circuit breaker to directly switch off the circuit breaker. And meanwhile, a transformer over-temperature tripping hard pressing plate is arranged at the dry type transformer breaker cabinet and used for switching in/out of an over-temperature protection tripping function.

The design of the over-temperature tripping loop of the dry type transformer can be seen to have certain potential safety hazards, the existing design is that a tripping outlet is realized by a temperature controller configured for the dry type transformer, an 'over-temperature tripping' contact is usually connected into a transformer comprehensive protection device, the transformer comprehensive protection device sends a tripping instruction to drive a high-voltage side circuit breaker and a low-voltage side circuit breaker of the dry type transformer to be switched off, or the over-temperature tripping loop is directly connected in parallel with a tripping control loop of the circuit breaker to directly switch off the circuit breaker. However, the over-temperature tripping loop of the dry-type transformer in the design belongs to typical single-contact protection, no other locking condition exists, once the dry-type transformer is immediately driven to trip at an outlet, certain unreliability exists, the possibility of mistakenly issuing a switching-off instruction by the temperature controller of the dry-type transformer exists under the special conditions of faults, aging damage and the like of the temperature controller of the dry-type transformer, and the mistaken switching-off of the dry-type transformer can be caused by cable short circuit and mistaken touch, so that the over-temperature tripping loop of the existing dry-type transformer has certain defects.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing a dry-type transformer is with novel excess temperature tripping circuit to eliminate current dry-type transformer excess temperature tripping circuit and adopt single contact tripping operation, protect the poor potential safety hazard of reliability, and make the dry-type become that the trouble can be recollected behind the excess temperature tripping operation, the quick seeking of the trouble of being convenient for, reduce the fault handling time, improve dry-type transformer operating stability.

The utility model provides a novel over-temperature tripping circuit for a dry type transformer, which comprises a temperature rise detection module, a three-phase two-out module and an over-temperature tripping module, wherein the temperature rise detection module comprises a three-phase temperature relay respectively connected with a A, B, C phase winding PCT thermistor of the dry type transformer and intermediate relays K1, K2 and K3 respectively connected with the three-phase temperature relay;

the two-out-of-three module comprises an input end and an output end, wherein the input end is composed of three groups of series loops consisting of K1 and K2, K2 and K3, and K3 and K1, and the output end is composed of the three groups of series loops in parallel;

the input end of the over-temperature tripping module and the output end of the two-out-of-three module are connected with the over-temperature tripping contact in series to form an AND gate circuit; and the output end of the over-temperature tripping module is connected with the non-electrical quantity protection input end of the dry-type transformer comprehensive protection device.

By means of the scheme, the novel over-temperature tripping loop for the dry-type transformer can fundamentally solve the potential safety hazard of poor reliability of single-contact tripping protection, so that faults can be recalled after the dry-type transformer is tripped over-temperature, the faults can be conveniently and quickly searched, the fault processing time is shortened, and the operation stability of the dry-type transformer is improved.

The above description is only an overview of the technical solution of the present invention, and in order to make the technical means of the present invention clearer and can be implemented according to the content of the description, the following detailed description is made with reference to the preferred embodiments of the present invention and accompanying drawings.

Drawings

Fig. 1 is a schematic structural diagram of a novel over-temperature trip circuit for a dry-type transformer of the present invention;

FIG. 2 is a schematic structural diagram of the temperature rise detection module of the present invention;

FIG. 3 is a schematic diagram of a two-out-of-three module according to the present invention;

FIG. 4 is a logic diagram of a two out of three module of the present invention;

FIG. 5 is a schematic diagram of the over-temperature trip of the present invention;

fig. 6 is the over-temperature trip logic diagram of the present invention.

Reference numbers in the figures:

1-temperature rise detection module; 2-a two-out-of-three module; and 3-an over-temperature tripping module.

Detailed Description

The following detailed description of the embodiments of the present invention is provided with reference to the accompanying drawings and examples. The following examples are intended to illustrate the invention, but are not intended to limit the scope of the invention.

Referring to fig. 1 to 6, the present embodiment provides a novel over-temperature trip circuit for a dry transformer, including a temperature rise detection module 1, a two-out-of-three module 2, and an over-temperature trip module 3, where the temperature rise detection module 1 includes a three-phase temperature relay connected to a PCT thermistor of a phase winding of the dry transformer A, B, C, and intermediate relays K1, K2, and K3 connected to the three-phase temperature relay, respectively;

the two-out-of-three module 2 comprises an input end and an output end, wherein the input end is composed of three groups of series loops consisting of K1 and K2, K2 and K3, and K3 and K1, and the output end is composed of three groups of series loops in parallel;

the input end of the over-temperature tripping module 3 and the output end of the two-out-of-three module 2 are connected with an over-temperature tripping contact (an over-temperature tripping pressing plate) in series to form an AND gate circuit; the output end of the over-temperature tripping module 3 is connected with the non-electrical quantity protection input end of the dry-type transformer comprehensive protection device.

The novel over-temperature tripping loop for the dry-type transformer can fundamentally solve the potential safety hazard of poor reliability of single-contact tripping protection, so that faults can be recalled after the dry-type transformer is subjected to over-temperature tripping, the faults can be conveniently and quickly searched, the fault processing time is shortened, and the operation stability of the dry-type transformer is improved.

The present invention will be described in further detail below.

1. Temperature rise detection module

A PCT thermistor of a phase winding of a dry type transformer A, B, C is correspondingly connected with a three-phase temperature relay, an action value is set (the constant value is set according to an over-temperature trip value of a temperature controller configured by the existing dry type transformer and can be set according to the temperature of less than 20-30 ℃, and the main purpose is to judge that the temperature of the dry type transformer winding actually rises), an action contact of each phase temperature relay is connected with an intermediate relay in series, and after each phase temperature relay acts, a normally open contact correspondingly drives the intermediate relays K1, K2 and K3 to act, so that a temperature rise detection module is formed. Please refer to fig. 2 for a schematic diagram and a logic diagram.

2 three-to-two module

The three-out-of-two module is built by utilizing normally open action contacts of the intermediate relay, the output ends (normally open action contacts) of the intermediate relay are respectively connected in series by K1 and K2, K2 and K3, and K3 and K1, and three groups of series circuits are connected in parallel to form the three-out-of-two module, so that misoperation caused by faults of individual temperature relays can be effectively avoided. Please refer to fig. 3 and 4 for schematic and logic diagram.

3. Over-temperature tripping module

And the three-out-of-two module and the over-temperature tripping module form a novel over-temperature tripping loop of the dry-type transformer, the over-temperature tripping loop is switched into the dry-type transformer for comprehensive protection and non-electric opening, and finally the dry-type transformer comprehensive protection device sends out a tripping instruction to drive the high-voltage side circuit breaker and the low-voltage side circuit breaker of the dry-type transformer to open. Please refer to fig. 5 and 6 for schematic and logic diagrams.

4. Jumping type transformer

The dry type transformer comprehensive protection non-electrical quantity is opened to receive an over-temperature tripping command, the dry type transformer comprehensive protection device sends out a tripping command to drive the high-voltage side circuit breaker and the low-voltage side circuit breaker of the dry type transformer to perform opening.

The utility model discloses when using, cause dry-type transformer really overtemperature when dry-type transformer because overload or other reasons, novel three-phase temperature relay that connects in PCT thermistor in the excessive temperature tripping circuit will move (be greater than 120 ℃), and open A, B, C three-phase temperature relay contact is constituteed gets two modules, judge the condition as the temperature rise that dry-type transformer operating temperature risees really, a plurality of formula transformer temperature risees to tripping temperature (be greater than 150 ℃), the temperature controller's of dry-type transformer configuration "excessive temperature tripping" contact will be opened, excessive temperature tripping module will satisfy the export condition this moment, satisfy the non-electric quantity protection tripping operation condition of dry-type transformer after the export is opened, send out tripping operation instruction by dry-type transformer integrated protection device, drive dry-type transformer is high, the low pressure side circuit breaker carries out the separating brake. The action set value of the dry type transformer A, B, C three-phase temperature relay can be properly reduced, and the main function is to determine that the actual operation temperature of the dry type transformer is increased, and the action set value and the excess temperature tripping contact form an AND gate circuit as a logic judgment condition, so that the false tripping of equipment caused by the false operation of a single contact in the original design of excess temperature tripping is prevented.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and it should be noted that, for those skilled in the art, a plurality of modifications and variations can be made without departing from the technical principle of the present invention, and these modifications and variations should also be regarded as the protection scope of the present invention.

Claims (1)

1. A novel over-temperature tripping circuit for a dry type transformer is characterized by comprising a temperature rise detection module, a two-out-of-three module and an over-temperature tripping module, wherein the temperature rise detection module comprises a three-phase temperature relay connected with a dry type transformer A, B, C phase winding PCT thermistor respectively and intermediate relays K1, K2 and K3 connected with the three-phase temperature relay respectively;

the two-out-of-three module comprises an input end and an output end, wherein the input end is composed of three groups of series loops consisting of K1 and K2, K2 and K3, and K3 and K1, and the output end is composed of the three groups of series loops in parallel;

the input end of the over-temperature tripping module and the output end of the two-out-of-three module are connected with the over-temperature tripping contact in series to form an AND gate circuit; and the output end of the over-temperature tripping module is connected with the non-electrical quantity protection input end of the dry-type transformer comprehensive protection device.

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