Design Of Comprehensive On-line Monitoring And Fault Diagnosis System For High-voltage Switchboard

The power switch cabinet accident reasons have much to do with the insulating property、overheating、the wrong operation, and mutations are often formed when failure occurs. This kind of contingency and emergency decide that it will lead to significant losses once failure occurs. Among them, wireless temperature measurement system is the important guarantee of high pressure equipment safety and stable operation. In the long-time working process of the transformer substation important electrical equipments, the power equipments like joint of the contactors and buses appear that temperature rises for aging or that the load current is too large, which could eventually lead to interruption of power supply suddenly even a fire accident. Therefore, realizing on-line monitoring and fault diagnosis system of intelligent switch can prevent accidents from happening early, which has the extremely vital significance on guaranteeing the normal operation of the high voltage switchgear, improving the power system reliability and automation degree of the operation.This paper designed a new type of comprehensive online monitoring control and fault diagnosis system of high-tension switch cabinet. Doing the on-line monitoring function analysis of the high voltage switchgear, design features included primary loop simulation figure showing(including circuit breaker state, hand trolley position or isolation knife state, grounding knife state, spring energy storage status display), high voltage hot-line instructions, high voltage electrified locking control, voice tips of mistakes, and environment temperature and humidity control, etc, it was the first time to make compatible with the function, which was online monitoring the temperature rising of the switchgear contactors. The system was mainly composed of modules of cabinet controlling the host intelligently, wireless converging node and contacts wireless temperature sensor. Among them, nine contacts wireless temperature sensor modules installed in circuit breaker or the contacts of cables, using for acquisition and sending contacts wireless temperature of9roads. Wireless gathering node was installed in the host controlled by cabinet intelligently, receiving the contacts’temperature from the nine wireless temperature sensor modules by ZigBee wireless way, then communicating with the host through the UART serial port to send the temperature received to the host for judgment and dealing with.Give the software and hardware design of that cabinets control the host computer intelligently. The Cygnal C8051F020microcontroller was used as the main control chip, monitoring the high voltage hot-line state of cabinet’s three phase and the running status of all the equipments in high voltage switch cabinets online; gathering environmental temperature and humidity in the cabinets and receiving the contactor wireless temperature real-timely; showing the situation of temperature and humidity and equipment running status through the liquid crystal、LED digital and LED indicator light; and given voice tips which prevented from making errors environment temperature and humidity control and high voltage electrified locking control. In addition, cabinet controlled the host computer intelligently by network communication of RS-485or CAN bus and daemon computer; finally completing real-time dynamic operation simulation and remote environment monitoring of electrically primary system constituted by many sets of switchgear.Give the design of the software and hardware of the wireless gathering nodes and contacts’wireless temperature sensor modules, which was a module of gathering and sending wireless temperature obtained by means of connecting the DS1820digital temperature sensor and the primary Chip Microprocessor MC9S08QG by Single bus way, and then communicated with MC13192by the way of SPI, sending contacts temperature to it and launching out through the antenna. Wireless gathering node was a reception module, it was MC13192that transfer the received temperature which was sent to the host of MC9S08QG through the antenna, then the MC9S08QG communicated with the intelligently controlled host through the UART serial, and sending the contacts temperature to the host computer of the intelligent switchgear.Give the software design of the monitoring center. The computer in the monitoring center connect every intelligent controlling host computer of the switchgear, then making real-time monitor mode and contacts temperature inquires on each intelligent controlling host computer of the current high-voltage switchgear cabinet, and completing the set,the collection, the storage, the inquires of the data and report output, etc.Finally this paper gives experimental study to this system; the experimental results show that the instructions of each switch state are all correct, the environmental humidity of the switchgear and the contacts temperature close to the actual value tested by the thermometer, and the errors are not more than0.5℃, the status of Audio Alert, human body induction, high-voltage charged block are normal; The technical index of the temperature and humidity control logic has fully met the requirements. The system also proceeded the field installation, Through the long time trial run, the system works stably, the wireless network is in security and reliable conditions, contacts temperature data are accurate, which has meet the various performance indicators that guarantee a power equipment’s safe operation.