Wang W.,Hunan University |
Luo A.,Hunan University |
Li Y.,Central South University |
Xu X.,Hunan Electrical Power Research Institute |
And 3 more authors.
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2012
The basic control rule applied to three-phase four-switch inverters (TFSI) for outputting three-phase balanced voltages is revealed. Based on this rule, a novel space vector pulse width modulation (SVPWM) algorithm is proposed in order to control the three-phase four-switch shunt active power filter (TFSSAPF). By introducing an advanced coordinate transform method, the proposed algorithm makes sure the basic voltage vectors to be on the coordinate axes in the two-phase stationary coordinate system, so that it only needs the four arithmetic operations of two line voltages to accomplish the selection of the basic voltage vector and the calculation of its function time. The proposed algorithm has the advantages of less detection units, less computation and higher accuracy than the traditional ones. As the output voltage vectors of the TFSSAPF have no zero-vectors, a so-called 'five segment type' algorithm is presented to synthesize the zero-vectors by forcing the durations of the voltage vectors which are equal in extent and opposite in phase equal to each other, which has the advantages of simply control logic and low harmonic contents of the output voltages. Simulation and experiment results show the validity and feasibility of the proposed algorithm. © 2012 Chin. Soc. for Elec. Eng.
Shu S.,Hubei Engineering University |
Ruan J.,Hubei Engineering University |
Huang D.,Hubei Engineering University |
Wu G.,Hubei Engineering University |
Liu C.,Fuzhou Electrical Power Industry Bureau
Proceedings - International Symposium on Discharges and Electrical Insulation in Vacuum, ISDEIV | Year: 2012
Starting from a transient equivalent model of a triple-break 126 kV vacuum circuit breaker (VCB) containing a dielectric reignition criterion, the reignition current waveform of the vacuum interrupter (VI) which took over the higher part of the transient recovery voltage (TRV) was simulated. A series damped resistor was added in the grading capacitor branch to extinguish the reignition current as early as possible. The results show that the effect of the damped resistor is optimal when its value is threshold between oscillatory and non-oscillatory decay. Excessive TRV which appeared across other un-reignition VIs and power frequency recovery voltage (PFRV) which appeared across the reignition VI were simulated. A metal oxide arrester (MOA) was installed in parallel with each VI to ensure breaking successfully by limiting the excessive TRV and PFRV. It is shown that the voltage limiting effect is preferable when a MOA with the reference voltage of 50 kV is in parallel with a grading capacitor of 1000 pF, also the thermal limit can be satisfied. Research results are expected to provide a basis for choosing proper dynamic voltage sharing measures for a triple-break 126 kV VCB. © 2012 IEEE.
Jiang N.,Fuzhou Electrical Power Industry Bureau |
Xie Y.,Fuzhou Electrical Power Industry Bureau |
Hou J.,State Grid Electric Power Research Institute of China |
Xu L.,Fuzhou Electrical Power Industry Bureau |
And 2 more authors.
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2010
With more and more cable-overhead mixed lines in power grid, it brings out a difficult problem for the operation department whether the reclosing device of the mixed line should be put into operation or not. This paper analyzes the influence of power cable type, laying mode and operating status of cable line on the reclosing mode of mixed lines. An instructional summary of reclosing mode is made and it directly provides the service for safe operation of power system. © 2010 State Grid Electric Power Research Institute Press.
Zhang F.,Fuzhou Electrical Power Industry Bureau |
Guo B.,Fuzhou Electrical Power Industry Bureau
Dianli Zidonghua Shebei/Electric Power Automation Equipment | Year: 2010
The combination of substation operation order generating system with programmed operation scheme is introduced. For the centralized and hybrid schemes, the substation operation order generating system is easily combined in the programmed operation server, while a computer is added in substation level for the distributed scheme to combine these two systems. Three points should be noticed: measures should be taken to assure the correct programmed operations after combining with the substation operation order generating system, such as the integrated online misoperation prevention software; the combination pattern of representative operation order and intelligent operation order should be more rational and applicable; both should be under closed-loop control.
Guo B.-Y.,Fuzhou Electrical Power Industry Bureau |
Zhang F.,Fuzhou Electrical Power Industry Bureau |
Luo S.,Fujian Provincial Electrical Power Training Center
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2010
In earth neutral system, zero-sequence protection of 220 kV transformer acts as earth-fault backup protection of bus and adjacent line, and considers internal earth-fault backup protection of transformer. For the fault of single phase high-resistance grounding occuring between current transformer and isolating switch laying aboard transformer, the motion analysis of transformer protection is conducted considering the case of circuit breaker refusal. The deficiency of trip setting is found that there is no protection to segregate faultless equipments with the fault. For the problem, a suggestion of adding another time to trip bus tie circuit breaker for zero-sequence protection of transformer II is put forward, which provides reference for trip setting of zero-sequence protection of 110 kV side of 220 kV transformer.