CN209894890U

CN209894890U - Grounding current on-line monitoring device for grounding iron core of transformer based on PLC

Info

Publication number: CN209894890U
Application number: CN201822108015.6U
Authority: CN
Inventors: 刘鹏; 王喆; 宋昆峰; 刘新宇; 袁文海; 陈兴; 陈臻; 董小顺; 谢堂文; 陈林; 韩昊; 汪兆奇; 艾尔江·马尔瓦西; 阿力木·买买提; 臧其贤; 邢占礼; 周保东
Original assignee: Urumqi Power Supply Co Of Xinjiang Power Co Ltd; State Grid Corp of China SGCC
Current assignee: Urumqi Power Supply Co Of Xinjiang Power Co Ltd; State Grid Corp of China SGCC
Priority date: 2018-12-16
Filing date: 2018-12-16
Publication date: 2020-01-03
Anticipated expiration: 2028-12-16

Abstract

The application relates to a grounding iron core grounding current online monitoring device based on a PLC (programmable logic controller) transformer, which comprises a current transformer for measuring a current value, a controller unit for processing the current value, an indicator lamp for displaying whether the current value is normal or not and an operating platform for performing online remote monitoring on the current value; the current transformer is connected in series with a grounding wire led out from a transformer iron core, the controller is connected to the current transformer side, the controller unit consists of a programmable controller and an analog quantity current input module, and a current normal indicator light and a current abnormal indicator light are connected to the programmable controller side in parallel; the programmable controller is connected with a first relay and a second relay, a control switch of the first relay is connected with the current normal indicator lamp in series, and a control switch of the second relay is connected with the current abnormal indicator lamp in series. The method and the device can directly display the normal and abnormal conditions of the grounding current of the transformer core.

Description

Grounding current on-line monitoring device for grounding iron core of transformer based on PLC

Technical Field

The application relates to a grounding iron core grounding current on-line monitoring device based on a PLC transformer.

Background

The power transformer is one of key equipment in a power system, is also a link with higher failure rate in the power equipment, and the normal operation of the power transformer is an important guarantee for the safe, reliable, high-quality and economic operation of the power system. When the power transformer operates normally, the iron core has to be grounded only a little reliably, no current loop exists in the iron core, and the current on the grounding wire is very small and is mostly milliampere; if two or more points of the iron core are grounded, circulation current can be generated in the iron core, the current on the grounding wire can be increased to dozens of amperes, the local overheating of the transformer can be caused, and even the local burning loss of the iron core can be caused in serious cases, so that the discharging fault is caused, and the reliable operation of the transformer and a power grid is seriously threatened.

At present, three methods are mainly used for detecting the grounding current of the transformer core, namely: periodically detecting the grounding current of the iron core by adopting a pincer-shaped ammeter; measuring the resistance value of the iron core to the ground by adopting a megger; and monitoring the gas chromatogram of the characteristic gas of the transformer insulating oil. The existing methods not only waste manpower and material resources, but also cannot perform regular measurement on some unattended substations, and leave potential safety hazards for the operation of electrical equipment of the substations.

Based on the above problems, a device for realizing online monitoring of the grounding current of the transformer core is necessary. And the running condition of the iron core in the transformer can be monitored in real time, and the method plays an important role in ensuring the normal running of the transformer.

Disclosure of Invention

In order to make up the defects of the existing transformer core grounding current monitoring device, the application provides the grounding current on-line monitoring device for the transformer core based on the PLC, which realizes the real-time monitoring of the grounding current of the transformer core, and the remote monitoring and alarming of the current value and the current abnormity.

The technical scheme of the application is realized as follows: the grounding iron core grounding current on-line monitoring device based on the PLC transformer comprises a current transformer for measuring a current value, a controller unit for processing the current value, an indicator lamp for displaying whether the current value is normal or not and an operating platform for carrying out on-line remote monitoring on the current value; the current transformer is connected in series with a grounding wire led out from a transformer iron core, the controller is connected on the side of the current transformer, the controller unit consists of a programmable controller S7-200PLC and an expansion module SM231 thereof, and a current normal indicator light and a current abnormal indicator light are connected in parallel on the side of the programmable controller S7-200 PLC; the programmable controller S7-200PLC is connected with a first relay and a second relay, a control switch of the first relay is connected with the current normal indicator lamp in series, and a control switch of the second relay is connected with the current abnormal indicator lamp in series. The expansion module SM231 is an analog current input module to which the aforementioned current transformer is connected.

The controller unit is connected with the remote operation platform through an RS485 communication interface.

The controller consists of a programmable controller S7-200PLC and an expansion module SM231 thereof, wherein the programmable controller converts current analog quantity detected by the current transformer into binary digital quantity which is used as the input quantity of the internal program of the controller, and the signal is output through the logic judgment of the program.

By implementing the technical scheme, the device is stable in operation, convenient to operate and capable of directly displaying the normal and abnormal conditions of the grounding current of the transformer core, and can monitor the grounding current of the transformer core in real time and remotely monitor and alarm whether the current value and the current are abnormal or not. In addition, the current measuring device can be communicated with a remote operation platform through an RS485 communication interface of S7-200PLC, and the current measured value can be displayed on the remote operation platform.

Drawings

The specific structure of the application is given by the following figures and examples:

FIG. 1 is a schematic structural diagram of the present application;

FIG. 2 is a controller external wiring diagram of the present application;

fig. 3 is a flowchart of a control procedure of the present application.

Legend: 1. transformer, 2, earth connection, 3, current transformer, 4, controller, 5, the normal pilot lamp of electric current, 6, the unusual pilot lamp of electric current, 7, RS485 communication interface, 8, remote operation platform.

Detailed Description

The present application is not limited to the following examples, and specific implementations may be determined according to the technical solutions and practical situations of the present application.

In the embodiment, as shown in fig. 1-3, the grounding current on-line monitoring device based on the PLC transformer grounding iron core includes a current transformer 3 for measuring a current value, a controller 4 for processing the current value, an indicator light for displaying whether the current value is normal or not, and a remote operation platform 8 for on-line remote monitoring the current value; the current transformer 3 is connected in series with a grounding wire 2 led out by a transformer iron core, the side of the current transformer 3 is connected with a controller 4, the controller 4 consists of a programmable controller S7-200PLC and an expansion module SM231 thereof, and the side of the programmable controller S7-200PLC is connected with a current normal indicator light and a current abnormal indicator light in parallel; the programmable controller S7-200PLC is connected with a first relay and a second relay, a control switch of the first relay is connected with the current normal indicator lamp 5 in series, and a control switch of the second relay is connected with the current abnormal indicator lamp 6 in series. The expansion module SM231 is an analog current input module to which the aforementioned current transformer 3 is connected.

The controller is connected with a remote operation platform 8 through an RS485 communication interface 7.

As shown in fig. 2, the controller 4 is composed of a programmable controller S7-200PLC and its expansion module SM231, the programmable controller converts the current analog quantity detected by the current transformer 3 into a binary digital quantity, which is used as the input quantity of the internal program of the controller, and outputs the signal through the logic judgment of the program.

As shown in fig. 2 and 3, firstly, the current transformer 3 collects the field current value and transmits the field current value back to the programmable controller S7-200PLC, and the field current value is compared with the normal value set in the program. If the collection value is in the range of the set value, the digital quantity port of the current normal indicator lamp is controlled to be powered on, the first relay coil is powered on, the current normal indicator lamp loop is conducted, and the current normal indicator lamp 5 is turned on. If the acquisition value is not in the range of the set value, the digital quantity port of the current abnormality indicator lamp 6 is controlled to be powered on, the second relay coil is powered on, the current abnormality indicator lamp loop is conducted, and the current abnormality indicator lamp 6 is turned on.

The remote operation platform 8 is a transformer core grounding current online monitoring interface, the monitoring interface is configured by adopting WinCC software, and the monitoring interface cannot directly exchange data with WinCC due to the fact that the monitoring interface is controlled by a programmable logic controller S7-200PLC and needs OPC software for bridging. The interface is provided with three functions of on-line display of a node current measured value, current normal indication and current abnormal indication, and can conveniently realize the on-line monitoring and alarming functions of the grounding current of the transformer core.

The transformer core grounding current on-line monitoring interface is provided with three functions of on-line display of a node current measured value, current normal indication and current abnormal indication, and can conveniently realize the on-line monitoring and alarming functions of the transformer core grounding current.

The technical characteristics form the embodiment of the application, the embodiment has strong adaptability and implementation effect, and unnecessary technical characteristics can be increased or decreased according to actual needs to meet the needs of different situations.

Claims

1. The utility model provides a based on PLC transformer ground connection iron core ground current on-line monitoring device which characterized in that: the current transformer is used for measuring a current value, the controller unit is used for processing the current value, the indicating lamp is used for displaying whether the current value is normal or not, and the operating platform is used for carrying out online remote monitoring on the current value; the current transformer is connected in series with a grounding wire led out from a transformer iron core, the controller is connected to the current transformer side, the controller unit consists of a programmable controller and an analog quantity current input module, and a current normal indicator light and a current abnormal indicator light are connected to the programmable controller side in parallel; the programmable controller is connected with a first relay and a second relay, a control switch of the first relay is connected with the current normal indicator lamp in series, and a control switch of the second relay is connected with the current abnormal indicator lamp in series.

2. The grounding iron core grounding current on-line monitoring device based on the PLC transformer as claimed in claim 1, wherein: the controller unit is connected with the remote operation platform through an RS485 communication interface.

3. The grounding iron core grounding current on-line monitoring device based on the PLC transformer as claimed in claim 1, wherein: the programmable controller converts the current analog quantity detected by the current transformer into binary digital quantity, and the binary digital quantity is used as the internal program input quantity of the controller, and the signal is output through the logic judgment of the program.