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Sun Y.,CYG SUNRUI Co. | Liu Y.,State Grid Corporation of China | Zhang L.,State Grid Corporation of China | Xu W.,State Grid Corporation of China
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2015

In a smart substation without any reserve for measurement and control device, when measurement and control device becomes abnormal or is in maintenance status, relevant bay will lose the measuring and control function. Though a double control device in mutual standby state solution has had some trial operation and mature realization technology, the cost of an additional device will hamper popularization and application of this solution. It has been found that centralized cold standby technology used in measurement and control function can cut down the cost of solving the problem of measurement and control device without reserve. A detailed description is made of model identification technology of the virtual measuring and control device used by centralized reserve, consistency verification technology, and the centralized reserve solution scheme. ©, 2015 Automation of Electric Power Press. Source


Yu Y.,State Grid Corporation of China | Qiu J.,State Grid Corporation of China | Wu Y.,CYG SUNRUI Co. | Tian J.,State Grid Corporation of China
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2014

As power grid grows increasingly strong, its capacity becomes bigger and the impedance of the buses becomes smaller. When a fault strikes at the end of a long transmission line, the sensitivity of circuit breaker failure protection's voltage blocking setting could become inadequate, which will leads to the circuit breaker failure and even protection failure. A novel circuit breaker failure blocking method based on current rather than voltage-only is proposed. The new method adopts the proportion of the current of the fault line and goes to the sum of the currents of all lines connected to the bus as the tripping threshold to unblock the circuit breaker failure blocking unit. The result of RTDS simulation has proved the new method is able to thoroughly solve the problem under discussion thoroughly. ©, 2014 State Grid Electric Power Research Institute Press. Source


Zhang G.-J.,CYG SUNRUI Co. | Liu Z.-Y.,State Grid Corporation of China | Wu Y.-C.,CYG SUNRUI Co. | Yu X.-J.,State Grid Corporation of China | Wei P.,State Grid Corporation of China
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2014

When the high resistance neutral point grounded system in wind farm occurs a single-phase fault, the conventional busbar differential protection has sensitivity problem. To avoid this situation, a high sensitivity differential protection based on the principle of waveform recognition is proposed, which identifies fault waveform characteristics, adjusts floating threshold according to real-time load and the differential ratio factor according to harmonic content of the system. The method can effectively avoid malfunction of high sensitivity differential protection caused by harmonic wave. RTDS simulation results show that this method can isolate fault quickly when a single-phase fault occurred in the high resistance neutral point grounded system. The application of the proposed method is of great significance to protecting electrical equipment and maintaining the stable operation of the wind system. ©, 2014, Power System Protection and Control Press. All right reserved. Source


Liu H.,CYG SUNRUI Co. | Li F.,State Grid Corporation of China | Li H.,State Grid Corporation of China | Yang J.,CYG SUNRUI Co.
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2015

The fault analysis relies on the wave record and logic diagram of relay protection. Due to the lack of protection logic diagram format standard definition and a unified analysis tool, complex fault analysis depends on protection factory. This paper presents an expression way of protection logic diagram based on SVG graphics. The standard logic diagram is formed by inputting logic cell, operator, connecting lines, etc., through standardized definition. The fault analysis is completed by the standardized recorded wave files and SVG file. The scheme proposed has been used in line protection device, which proves the feasibility of the scheme. ©, 2015, Power System Protection and Control Press. All right reserved. Source


Sun Y.,CYG SUNRUI Co. | Liu H.,CYG SUNRUI Co. | Jiang J.,State Grid Corporation of China | Yang Y.,State Grid Corporation of China
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2014

By comprehensive use of online cyclic redundancy check (CRC) code control, comparative analysis for configuration of the virtual circuit and visual check for the virtual circuit of substation configuration description (SCD) file, the devices whose configuration should be upgraded synchronously with SCD file can be determined. Through comparative analysis of the characteristics of hardware circuit and the virtual circuit of the secondary system in the substation, the completeness of the SCD file control strategy is proposed and proved. In the case of the busbar protection expansion project, the control scheme for the SCD file is analyzed. Source

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