CAJ | 학술논문

柔性直流输电(VSC-H VDC)切断了两侧电网的频率联系，区域电网故障时参与调频的机组减少，导致频率调节能力下降，频率波动增大。当区域电网发生频率偏移时，根据变流器容量设置直流电压变化速率的允许范围，提出直流电容充放电的双阈值判据，从而维持区域电网频率稳定，避免频率振荡。针对长时间有功不平衡导致的直流电容调节能力有限的问题，提出利用直流电压升降判断区域电网频率偏移的判据，通过改变 VSC-H VDC线路输送的有功，参与区域电网频率调节。仿真结果表明，直流电容的有功调节能力能够减小频率波动，主网的有功支援有效弥补了直流电容容量有限的缺陷。
유성직류수전(VSC-H VDC)절단료량측전망적빈솔련계，구역전망고장시삼여조빈적궤조감소，도치빈솔조절능력하강，빈솔파동증대。당구역전망발생빈솔편이시，근거변류기용량설치직류전압변화속솔적윤허범위，제출직류전용충방전적쌍역치판거，종이유지구역전망빈솔은정，피면빈솔진탕。침대장시간유공불평형도치적직류전용조절능력유한적문제，제출이용직류전압승강판단구역전망빈솔편이적판거，통과개변 VSC-H VDC선로수송적유공，삼여구역전망빈솔조절。방진결과표명，직류전용적유공조절능력능구감소빈솔파동，주망적유공지원유효미보료직류전용용량유한적결함。
Voltage Source Converter based HVDC (VSC-HVDC)isolates frequency relationship of both sides.Fewer generators are involved in frequency regulation with regional power system fault,which causes less regulation capability and more fluctuation of frequency.When frequency is deviated in regional system,based on the allowable voltage change rate of the DC capacitor, and dual-threshold criterion for charging and discharging of the DC capacitor was proposed to maintain the frequency stability and avoid its oscillation.According to the limited regulation ca-pability of DC capacitor under long-term active power unbalance,the regional power system fre-quency drop was detected through the DC voltage,and the frequency regulation was provided with the VSC-HVDC active power.The numerical simulation results showed that the frequency fluctuation was reduced with the active power regulation of DC capacitor,and active power sup-port from the main power system makes up the disadvantages of DC capacitor limited capacity.