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Zhou L.,China Electronic Power Research Institution | Tang G.,China Electronic Power Research Institution | Hao C.,China Electronic Power Research Institution | Yang M.,Hefei University of Technology
Dianwang Jishu/Power System Technology | Year: 2011

A control strategy to avoid the malfunction of converter control and protection (CCP) system due to missing firing pulses of valve basic electronics (VBE) is proposed. The core idea of the proposed control strategy consists in the design of algorithm, namely once the pulse missing in the trigger signal, which is transmitted by CCP system via Ethernet links to the gate unit (GU) of the valve, is detected, the VBE does not do anything; based on operational experiences and mathematical statistics, when the missing of four consecutive pulses with duration of 80 ms is detected, according to the proposed control strategy the VBE sends the fail signal to CCP system to ask for the switching. The VBE system adopting the proposed control strategy is applied in the coordinate control experiments of real-time digital simulator, and experiment results show that the proposed control strategy can effectively eliminate the danger caused by existing protection methods and reduce the malfunction probability of CCP system. Source


Chen Z.,China Electronic Power Research Institution | Tang G.,China Electronic Power Research Institution | Wei X.,China Electronic Power Research Institution | Chen L.,China Electronic Power Research Institution
Dianwang Jishu/Power System Technology | Year: 2012

In allusion to the false triggering that appears due to the time delay procreated in pulse frequency conversion while the switching-in of bypass pair is finished, a control strategy based on shortest job first algorithm is proposed, The core idea of the proposed control strategy is as following: when the operation of switching-in of bypass pair finished, the signal frequency, whether which is 10 kHz or 1 MHz, is not directly detected, but in the program it is previously regarded that the bypass pair order (BPPO) possesses two states, namely 0 and 1, when the signal frequency is 1 MHz, the BPPO is set as 1 and set as 0 for other conditions, thus the switching-in of bypass pair is regarded as finished when the detected state of BPPO is not 1. Because the time delay of this process is only several microseconds, so in the duration of this short time delay, the control pulse cannot be recognized, therefore the false triggering can be avoided effectively. The valve base electronics (VBE) designed according to the proposed control strategy is applied in the coordinate control test of real time simulator (RTDS). Test results show that the proposed control strategy can effectively eliminate the short-circuit current due to false triggering caused by original control method, thus the malfunction probability of converter control and protection (CCP) system is reduced. Source

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