Sifang Electrical Group Co.

Haidian District, China

Sifang Electrical Group Co.

Haidian District, China
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Xie X.-R.,Tsinghua University | Guo X.-J.,Autonomous Corporation | Wu J.-L.,Autonomous Corporation | Li G.-B.,Autonomous Corporation | And 5 more authors.
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2010

Filed tests were conducted to validate the effectiveness of supplementary excitation damping control (SEDC) for mitigating subsynchronous resonance (SSR) in Shangdu series-compensated transmission system. The operating conditions, testing procedures and main results of the test are presented. The test shows that the system is threatened by SSR, especially the torsional mode No.2, which tends to diverge under the operating condition of 3 or 4 machines online and one Shangdu-Chengde line in service. SEDC can considerably enhance torsional damping, and thus effectively depress SSR. Field tests were carried out under different system conditions and with various operations, demonstrating the robustness of the developed SEDCs. Comparative analysis has also been performed between field tests and the simulation study, which indicates good consistence between them. This is the first time in China that practical SEDCs have been developed and their effectiveness in damping SSR has been verified in a real series-compensated system. It represents an important step toward engineering application of SEDC in SSR-mitigation in China. © 2010 Chin. Soc. for Elec. Eng.

Xie X.,Tsinghua University | Guo X.,Autonomous Corporation | Wu J.,Autonomous Corporation | Zhao Y.,Autonomous Corporation | And 3 more authors.
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2014

A novel generator terminal subsynchronous damping controller (GTSDC) based on power electronic converter was proposed and developed to mitigate subsynchronous resonance (SSR), a serious problem confronted by larger turbine-generators connected to series-compensated power systems. The proposed GTSDC is composed of a multimodal subsynchronous damping controller and a high-power current-tracking inverter. It can depress the torsional vibration by injecting controllable currents at complementary frequencies to torsional modes into the stator of the target generator. Its working principle and designing approach were elaborated in the paper. A practical equipment with a rating of 10 MVA/22 kV had been manufactured and then tested on a 660 MW turbine-generator at Shangdu Power Plant. Test results verified that GTSDC can improve modal damping considerably and suppress sustained torsional oscillation effectively. It provides a new countermeasure to inhibit subsynchronous resonance and oscillation. © 2014 Chin. Soc. for Elec. Eng.

Xie X.,Tsinghua University | Wang L.,Tsinghua University | Guo X.,Northern United Power Corporation | Jiang Q.,Tsinghua University | And 2 more authors.
IEEE Transactions on Power Electronics | Year: 2014

This paper presents a novel controlling device, named generator terminal subsynchronous damper (GTSSD), to mitigate subsynchronous resonance (SSR) in the power system. The proposed GTSSD consists of a multimodal complementary current calculator (MCCC) and a complementary current generator (CCG). The CCG is composed of a current tracking controller and a power-electronic converter. The rotor speed deviation of the generator is fed back to the MCCC to calculate the current references of the CCG. The outputs of CCG consist of both sub-and supersynchronous complementary current, part of which flows into the generator and creates damping torque on the rotor. The relationship between the control parameters of the GTSSD and the resultant damping improvement is derived. A 10-MVA GTSSD prototype has been developed and tested in an actual series-compensated power system. The experimental results fully demonstrate its ability to enhance torsional damping and to depress subsynchronous oscillation, proving that the GTSSD provides a new and effective approach to solve SSR problems. © 2013 IEEE.

Chen D.-Y.,Shangdu Power Plant Co. | Zhao Y.-L.,Shangdu Power Plant Co. | Liu Q.,Sifang Electrical Group Co. | Zhang Y.-Q.,Tsinghua University | Xie X.-R.,Tsinghua University
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2010

A subsynchronous torsional protection scheme is developed to protect generator shafts from damage caused by subsynchronous resonance (SSR). The scheme is composed of the bottom-layered torsional stress relay (TSR) and the upper-layered coordinator, called Tmaster. The TSR gathers the modal speed of generator shafts in real time and detects dangerous SSR according to the criteria of torsional stability and fatigue loss-of-life. The Tmaster coordinates the response from multiple TSRs and trips generators selectively. The proposed ″TSR+Tmaster″ scheme is implemented for the Shangdu series-compensated transmission system, of which the operation principle and the protection setting are elaborated in this paper. Since it was put into practice in September 2008, the protection system has experienced various field tests and real system faults, demonstrating its effectiveness in detecting subsynchronous vibration and protecting generator shafts.

Li J.,Beijing Information Science and Technology University | Jiao S.,Sifang Electrical Group Co. | Wen Y.,Beijing Information Science and Technology University | Wang H.,Beijing Information Science and Technology University
2010 China International Conference on Electricity Distribution, CICED 2010 | Year: 2010

This paper introduces an online insulation monitoring system of high-voltage capacitive substation equipment based on Zigbee wireless sensor network. According to the voltage level, a number of Zigbee subnets are installed in the substation to measure the leakage current of the capacitive equipment with the improved accuracy and reliability of the measurement. The clocks of different devices are synchronized to realize the synchronized phase measurements and achieve the precise dielectric loss factor. Several Zigbee subnets construct the sensor net of the substation capacitive equipment state monitoring system. The monitoring master of capacitive devices can be included in the intelligent substation automation system as interval level devices, and can also be connected to a distance substation monitoring master through 3G communication network. © 2010 Chinese Soc for Elec Eng.

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