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Shao Z.-Y.,Nanjing Hongyi Electrical Automation Co. | Tian W.,Nanjing Hongyi Electrical Automation Co. | Lu Y.-B.,Nanjing Hongyi Electrical Automation Co.
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2014

At present, many 110 kV distribution stations adopt double loop series connection mode, which makes the present remote automatic bus transfer devices unapplicable. So the paper proposes a new general remote automatic bus transfer method based on the optical fiber communication. The distribution stations connected in series can exchange information with each other. The traditional bus based method is extended to the working line based method. If the working power is powered off for some reason, the nearest switch to the fault point will be switched off and the nearest switch to the power point will be switched on, so the system power supply will be recovered as far as possible. The method is simple, applicable and practical.


Shao Z.-Y.,Nanjing Hongyi Electrical Automation Co. | Tian W.,Nanjing Hongyi Electrical Automation Co. | Lu Y.-B.,Nanjing Hongyi Electrical Automation Co.
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2011

Distance protection is required to rapidly block protection when detecting power swings and rapidly unlock protection when the symmetrical fault occurring during power swings. It is difficult to rapidly identify the symmetrical fault during power swings. In this respect, this paper discusses the electrical characteristics of power swings and symmetrical fault during power swings, and brings forward a new method based on U cosφ waveform characteristics to rapidly identify the symmetrical fault during power swings. The paper proves that the difference of U cosφ waveform between power swings and symmetrical fault is clear and adequate resolution can be obtained in a short time, so this method can quickly detect power swings when they occur and block the distance protection. Besides, it can also unblock the distance protection as soon as the symmetrical fault occurs during power swings. This method has a clear physical meaning, simple calculation, short identification delay and no relation with system parameters, fault moment, and fault location.


Li C.-F.,Nanjing Hongyi Electrical Automation Co. | Chen F.,Nanjing Institute of Technology | Lu Y.-B.,Nanjing Hongyi Electrical Automation Co. | Tian W.,Nanjing Hongyi Electrical Automation Co.
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2010

Noticed the fact that there is no fast protection for medium and low voltage currently, the first domestic set of arc protection relay system DPR360ARC is designed. This system applies the techniques of arc probe technology based on UV sensors and high-speed serial communication technology based on FPGA, and realizes the rapid protection for bus and switchgear. The time from arc occurs to the export trips can be limited to 4 ms, which greatly improves the reliability of medium and low voltage transmission line. Also, this system can provide overall protection corresponding to the arc faults of bus, switchgear, kinds of rectifier equipment, greatly reduce the risk of equipment's damage and worker's death, and ensure the grid's safe and smooth recovery.

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