CN214151002U

CN214151002U - Circuit for high-temperature reactor auxiliary low-voltage side branch single-phase grounding alarm

Info

Publication number: CN214151002U
Application number: CN202023050604.7U
Authority: CN
Inventors: 朱兴文; 董毓晖; 徐西家; 邢艳平; 李小龙
Original assignee: Huaneng Shandong Shidaobay Nuclear Power Co Ltd
Current assignee: Huaneng Shandong Shidaobay Nuclear Power Co Ltd
Priority date: 2020-12-17
Filing date: 2020-12-17
Publication date: 2021-09-07
Anticipated expiration: 2030-12-17

Abstract

A circuit for a high-temperature reactor auxiliary low-voltage side branch single-phase grounding alarm is characterized in that a 110kV nuclear line is connected with the high-voltage side of an auxiliary transformer through a No. 111-3 isolating knife and a No. 111 switch, and the low-voltage side of the auxiliary transformer is connected with a 6kV C section bus through a No. 6kV C section incoming line 6023 switch; the 6kV C section bus is connected with the 6kV auxiliary boiler section bus through a No. 6kV auxiliary boiler section incoming line 6024 switch; the 6kV auxiliary boiler section bus is connected with the primary side of an auxiliary boiler section bus PT; and the auxiliary boiler section bus PT secondary side opening triangular winding is connected with a zero sequence voltage protection device K01. The invention can inform operators of the working condition of the branch bus at the low-voltage side of the auxiliary transformer in the first time, and can immediately take precautionary measures once a single-phase earth fault occurs, thereby avoiding the expansion of accidents and power failure and ensuring the safe and stable operation of the auxiliary transformer system.

Description

Circuit for high-temperature reactor auxiliary low-voltage side branch single-phase grounding alarm

Technical Field

The utility model relates to a circuit especially relates to a be used for supplementary step-down voltage side branch single-phase ground connection warning circuit of high temperature heap.

Background

The electric power system can be divided into a large-current grounding system and a small-current grounding system according to the grounding mode of a neutral point, and the 6kV medium-voltage distribution network in China mostly adopts the mode that the neutral point is not directly grounded, and is also called as the small-current grounding system. In various faults under the mode, a single-phase earth fault is the most common system fault, when the fault occurs, a non-fault phase voltage can be increased to a line voltage to cause system overvoltage, the fault is brought for a long time to operate, insulation damage is easily caused, arc short circuit grounding is generated, two-point earth faults are formed, and system safety is seriously influenced.

Generally, a single-phase ground fault can be timely discovered and processed through zero-sequence voltage acquired by a PT open delta winding. However, in a special operation mode, for example, in a transformer in a hot standby state, a low-voltage side branch bus of the transformer is often in the hot standby state for a long time, and if a PT of a transformer low-voltage side branch does not have an open triangular winding, when a single-phase ground fault occurs in the transformer low-voltage side branch, zero-sequence voltage cannot be acquired, so that a connection cable (or a busbar) between a transformer low-voltage side bushing and a downstream bus switch cabinet becomes a dead zone of a conventional voltage monitoring device, and potential safety hazards are brought to safe and stable operation of a power supply system.

According to the 110kV auxiliary variable power supply system wiring mode of the high-temperature gas cooled reactor demonstration project, the high-temperature gas cooled reactor auxiliary variable-low voltage side incoming line PT does not have an open triangular winding, and only the 6kV bus line PT has the open triangular winding, so that the insulation condition of the auxiliary variable-low voltage side branch bus line cannot be monitored by the open triangular winding of the auxiliary variable-low voltage side incoming line PT, namely when auxiliary variable-low voltage side branch bus line is in single-phase grounding, no alarm information exists, and great potential safety hazard is brought to stable operation of the 110kV system.

SUMMERY OF THE UTILITY MODEL

In order to solve the defect among the prior art, the utility model discloses a be used for supplementary step-down of high temperature heap to incline branch single-phase ground connection warning circuit.

The technical scheme is as follows:

a circuit for high-temperature reactor auxiliary low-voltage side branch single-phase grounding alarm comprises an auxiliary transformer incoming line 111-3 isolating knife, an auxiliary transformer incoming line 111 switch, an auxiliary transformer, a 6kV C section incoming line 6023 switch, a 6kV auxiliary boiler section incoming line 6024 switch and a 6kV auxiliary boiler section bus PT; it is characterized in that: the 110kV nuclear power line is connected with the high-voltage side of the auxiliary transformer through a No. 111-3 isolating knife and a No. 111 switch, and the low-voltage side of the auxiliary transformer is connected with a 6kV C section bus through a No. 6kV C section incoming line 6023 switch; the 6kV C section bus is connected with the 6kV auxiliary boiler section bus through a No. 6kV auxiliary boiler section incoming line 6024 switch; the 6kV auxiliary boiler section bus is connected with the primary side of an auxiliary boiler section bus PT; and the auxiliary boiler section bus PT secondary side opening triangular winding is connected with a zero sequence voltage protection device K01.

Preferably: the low-voltage side of the auxiliary transformer is connected with a 6kV A section bus through a 6kV A section incoming line 6021 switch; and the 6kV A section bus is connected with the A section bus PT.

Preferably: the low-voltage side of the auxiliary transformer is connected with a 6kV B section bus through a 6kV B section incoming line 6022 switch; and the 6kV B section bus is connected with a B section bus PT.

Preferably: and the low-voltage side of the auxiliary transformer is also connected with the section A incoming line PT, the section B incoming line PT and the section C incoming line PT respectively.

Preferably: and the secondary side of the auxiliary boiler section bus PT is provided with an open triangular winding.

Preferably: when the incoming line branches of the 6kV A section, the 6kV B section and the 6kV C section have single-phase earth faults, the PT opening triangular winding of the bus bar of the 6kV auxiliary boiler section collects zero sequence voltage, when the zero sequence voltage value exceeds the zero sequence voltage alarm fixed value, the zero sequence voltage protection device K01 alarms and acts to light, and meanwhile, a zero sequence voltage alarm signal is uploaded to the DCS.

Advantageous effects

When the auxiliary transformer is in hot standby, a common box bus between a low-voltage side sleeve of the auxiliary transformer and a 6kV bus switch cabinet is a dead zone of traditional voltage monitoring, and a high-temperature gas cooled reactor demonstration project auxiliary transformer low-voltage side branch bus incoming line PT does not have an opening triangular winding, so that the single-phase grounding condition of the auxiliary transformer low-voltage side branch bus cannot be monitored by adopting zero-sequence voltage measured by the PT opening triangular winding commonly used in the industry. The potential safety hazard brought by the monitoring dead zone to the operation of the auxiliary transformer of the high-temperature gas cooled reactor demonstration project is thoroughly avoided. The method innovatively utilizes zero sequence voltage measured by an open triangular winding of a 6kV auxiliary boiler section bus PT to monitor the single-phase earth fault condition of a branch bus at the low-voltage side of an auxiliary transformer. The monitoring dead zone problem has been solved to this mode, can inform the operating personnel in the very first time and assist the operating mode of transformer low pressure side branch bus, in case single-phase earth fault takes place, can take precautionary measure the very first time, avoids the expansion and the power failure of accident, guarantees the safe and stable operation of auxiliary transformer system.

Drawings

Fig. 1 is a schematic diagram of the utility model discloses a single-phase ground connection warning circuit for supplementary low-voltage side branch of high temperature reactor.

Fig. 2 is the circuit flow diagram of the utility model for the supplementary low-voltage side branch single-phase grounding of high temperature reactor is reported to the police.

Detailed Description

In order to make the technical solution of the present invention better understood by those skilled in the art, the present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.

A single-phase ground connection alarm circuit for high temperature reactor auxiliary low-voltage side branch comprises an auxiliary transformer incoming line 111-3 isolating knife, an auxiliary transformer incoming line 111 switch, an auxiliary transformer, a 6kV C section incoming line 6023 switch, a 6kV auxiliary boiler section incoming line 6024 switch and a 6kV auxiliary boiler section bus PT. The 110kV nuclear power line is connected with the auxiliary transformer high-voltage side through a 111-3 isolation knife and a 111 switch, the auxiliary transformer low-voltage side is divided into 3 branches which are respectively an A branch, a B branch and a C branch, wherein the A branch mainly comprises a 6kV A section 6021 switch, an A section incoming line PT, an A section bus and an A section bus PT, the B branch mainly comprises a 6kV B section 6022 switch, a B section incoming line PT, a B section bus and a B section bus PT, the C branch mainly comprises a 6kV C section 6023 switch, a C section incoming line PT, a C section bus, a 6kV auxiliary boiler section incoming line 6024 switch, a 6kV auxiliary boiler section bus and a 6kV auxiliary boiler section bus PT. Two ends of an open triangular winding of a 6kV auxiliary boiler section bus PT for measuring zero sequence voltage are connected to 109 and 110 terminals of a K01 protection device for judging zero sequence protection logic.

The working principle is as follows, and is shown in figure 2:

1. checking and confirming that the open delta winding of the 6kV auxiliary boiler section bus PT is connected to the 109 and 110 terminals for zero sequence voltage protection of the K01 protection device in the figure 1, simultaneously putting zero sequence voltage protection on the 6kV auxiliary boiler section bus PT protection device, and setting the action mode to alarm.

2. When auxiliary transformer substation is in standby, namely the 6kV A section incoming line 6021 switch and the 6kV B section incoming line 6022 switch are in an open state, the 6kV C section incoming line 6023 switch and the 6kV auxiliary boiler section incoming line 6024 switch are kept in a closed state, meanwhile, the auxiliary boiler section bus PT is put into an operating state, and the monitoring of the insulation condition of the auxiliary transformer substation side branch bus is realized through zero-sequence voltage measured by an opening triangular winding of the 6kV auxiliary boiler section bus PT.

3. When the auxiliary low-voltage side branch has a single-phase ground fault, because the auxiliary low-voltage side branch is a neutral point ungrounded system, when the single-phase ground fault occurs, the related protection cannot be directly operated to trip, namely, the 111 switch, the 6021 switch, the 6022 switch, the 6023 switch and the 6024 switch cannot trip, but the fault phase voltage is reduced to zero, and the voltage of the other two phases rises to 1.732 times of the phase voltage, at the moment, the line voltage of the system is still normal but still needs to be processed in time, otherwise, the non-fault two phases run at a high voltage for a long time, and the two-phase ground or the three-phase ground is possibly short-circuited, so that more loss is caused. After the auxiliary transformer low-voltage side 6kV ungrounded system has a single-phase grounding fault, the PT opening triangular winding of the 6kV auxiliary boiler section bus bar collects zero-sequence voltage, when the zero-sequence voltage value exceeds a zero-sequence voltage alarm fixed value, a zero-sequence voltage alarm action lamp of the K01 protection device is turned on, and meanwhile, a zero-sequence voltage alarm signal is uploaded to a DCS to inform operators.

The utility model discloses a according to high temperature gas cooled reactor 110kV electrical power generating system wiring mode, adopt the operation mode of closing 6kV C section switch and the supplementary boiler section switch of 6kV and generating line PT, utilize generating line PT opening triangular winding of the supplementary boiler section of 6kV to realize monitoring the zero sequence voltage of auxiliary transformer low pressure side branch generating line. Compared with the traditional way of replacing the PT with the open delta winding on the low-voltage side branch PT of the transformer. The utility model discloses do not relate to the once big rectification in the aspect of electric, also need not to found item, purchase, installation and longer test cycle, it is less to the field work progress influence, especially adapted engineering stage goes on.

It is to be understood that the above embodiments are merely exemplary embodiments adopted to illustrate the principles of the present invention/utility model, but the present invention/utility model is not limited thereto. It will be apparent to those skilled in the art that various modifications and improvements can be made without departing from the spirit and substance of the invention/utility model, and these modifications and improvements are also considered to be within the scope of the invention/utility model.

Claims

1. A circuit for high-temperature reactor auxiliary low-voltage side branch single-phase grounding alarm comprises an auxiliary transformer incoming line No. 111-3 isolating knife, an auxiliary transformer incoming line No. 111 switch, an auxiliary transformer, a 6kV C section incoming line No. 6023 switch, a 6kV auxiliary boiler section incoming line No. 6024 switch and a 6kV auxiliary boiler section bus PT; it is characterized in that: the 110kV nuclear power line is connected with the high-voltage side of the auxiliary transformer through a No. 111-3 isolating knife and a No. 111 switch, and the low-voltage side of the auxiliary transformer is connected with a 6kV C section bus through a No. 6kV C section incoming line 6023 switch; the 6kV C section bus is connected with the 6kV auxiliary boiler section bus through a No. 6kV auxiliary boiler section incoming line 6024 switch; the 6kV auxiliary boiler section bus is connected with the primary side of an auxiliary boiler section bus PT; and the auxiliary boiler section bus PT secondary side opening triangular winding is connected with a zero sequence voltage protection device K01.

2. The circuit for the high temperature stack auxiliary low voltage side branch single phase grounding alarm according to claim 1, characterized in that: the low-voltage side of the auxiliary transformer is connected with a 6kV A section bus through a 6kV A section incoming line 6021 switch; and the 6kV A section bus is connected with the A section bus PT.

3. The circuit for the high-temperature stack auxiliary low-voltage side branch single-phase grounding alarm as claimed in claim 2, wherein the circuit comprises: the low-voltage side of the auxiliary transformer is connected with a 6kV B section bus through a 6kV B section incoming line 6022 switch; and the 6kV B section bus is connected with a B section bus PT.

4. The circuit for the high-temperature stack auxiliary low-voltage side branch single-phase grounding alarm as claimed in claim 2, wherein the circuit comprises: and the low-voltage side of the auxiliary transformer is also connected with the section A incoming line PT, the section B incoming line PT and the section C incoming line PT respectively.

5. The circuit for the high temperature stack auxiliary low voltage side branch single phase grounding alarm according to claim 1, characterized in that: and the secondary side of the auxiliary boiler section bus PT is provided with an open triangular winding.

6. The circuit for the high temperature stack auxiliary low voltage side branch single phase grounding alarm according to claim 3, characterized in that: when the incoming line branches of the 6kV A section, the 6kV B section and the 6kV C section have single-phase earth faults, the PT opening triangular winding of the bus of the 6kV auxiliary boiler section collects zero sequence voltage, when the zero sequence voltage value exceeds the zero sequence voltage alarm fixed value, the zero sequence voltage protection device K01 alarms and acts to light, and meanwhile, a zero sequence voltage alarm signal is uploaded to the DCS.