In recent years, metal oxide (MOA) gapless arrester has protective properties superior, through flow capacity, simple structure, light weight, less maintenance, therefore in the power system is widely used.
MOA arrester performance will directly influence the safe operation of power system, because of MOA arrester long-term in power under the action of a high voltage, will gradually aging, instead of once a year - Test to find the aging of MOA arrester is not enough, even in the pre test qualified MOA lightning arrester, occurrence breakdown may in operation, the protection characteristics of decline, it will have serious consequences, in order to ensure the safe operation of MOA arrester, must carry on the strict monitoring of MOA surge arrester.
The monitoring methods of MOA arrester lightning arrester is used to realize on-line monitoring monitor, it works in the operating voltage is normal, the lightning arrester leakage current by the change of current meter measured, when the flow through the action current strong will from the leakage current measurement circuit is transferred to the loop counter, to achieve the record of the number of action by action current energy counter action. A lightning arrester monitor, guidelines prescribed daily reading time, in addition to record the leakage current, should also record the time, operating voltage, environmental temperature, weather conditions and other parameters, supervision and management. These methods must rely on manpower to complete, but also have certain limitations, not negligence, in manual inspections and a timeliness poor, often can not be found hidden in a timely manner. If not found in time, become accident signs of danger and.
In recent years, in order to solve the transmission problem, launched an online monitoring of MOA arrester transmission system, its working principle of the current arrester monitor measured (leakage current) is converted into an optical pulse signal, the optical fiber transmission of light by a photoelectric converter bus line 485, remote function, its working process is the current MOA surge arrester to charge the capacitor, the voltage of two terminal capacitor rises gradually end and timer chip comparison when the capacitor voltage is greater than the two end of the end of the comparison voltage comparison, the output timer chip from high level to low level or low level to high level, the driver stage light emitting diodes and the discharge of the capacitor to form a voltage frequency conversion circuit, to achieve an ideal circuit passive signal optical fiber transmission. This method solves the data transmission problem, but there are many problems in the practical process, some installation in less than six months will not work. In 1 the voltage to frequency circuit in the capacitance of the capacitor value is not stable by ambient temperature change change, after testing, the ambient temperature below 5 degrees or 30 degrees above the current display value detection and remote signal is not stable, the ambient temperature at minus the detection current display value and far transmission is not working. The pressure of light diode frequency circuit, the starting current very discrete, caused by measurement results and remote signal instability; and 2 fiber easily affected by external factors, such as: the wind beam caused by optical fiber connector from in situ cause system HERSHEY'S bad; skin optical fiber can not resist ultraviolet light in sunlight exposure time optical fiber, skin aging local cracked after receiving external light transmission is caused by abnormal. Optical interface Water Leakage ○ 3 monitor is more serious and the photoelectric converter also has bad sealing, not up to the water level requirements.
Through the introduction of the above, the monitoring of the MOA lightning arrester must adopt a "online, real-time, remote monitoring, intelligent, reliable" way, but the current monitoring methods commonly used are not effective, reliable data transmission. The unattended substation integrated automation system and substation operation management system can not well support.
Two, system overview
With the development of power enterprises in technological progress, 110kV has a lot of unattended substation, 220kV substation unattended also has entered the implementation stage. The use of technical means, realize the monitoring center for Unattended Substation Operator on the substation equipment condition can effectively monitor.
BLQ－1 MOA arrester monitoring and management system (hereinafter referred to as the system), is my company for power system of unmanned substation (the) need high-tech new product research and development.
This system is mainly used for all current monitoring for high voltage AC gapless MOA arresters in under operating voltage (leakage current), discharge action date, time and discharge action cumulative number of times, the current detection with single turn a through core current sensor sampling mode, the full isolation, advanced microprocessor technology and unique transient the techniques for measuring the parameters of linear processing and calculation, the measured results of digital transmission by bus: the reliability and security of the system with high and low price, so that the system can be installed in each group of MOA arrester for real-time detection, realize centralized monitoring, operation condition of copying MOA arrester without operation personnel daily to the scene trivial, do the accurate and timely grasp the operation of the health status of the equipment, the background management system of computer monitoring center, multi substations (the) centralized monitoring unit of data receiving and forwarding the computer serial port to read data, and specify a fixed IP background management system, through the B / S pattern of network sharing, relevant personnel can the data view points through local area network.