CAJ | 학술논문

同步误差在差动保护中表现为相移,同步误差引起的安全性问题可以用差动保护的相移制动能力描述.本文首先分析了传统比率制动判据的相移制动能力,发现获取良好的相移制动能力必须牺牲算法的灵敏度.为了适应弱同步环境,本文提出了一种新的差动保护判据,新判据分别从幅值和相角两个方面独立形成制动约束,从而可以合并解决电流互感器和同步误差引起的不平衡电流问题.新判据的制动区在ρ平面上呈现扇环形状,扇环内径决定了判据的灵敏度,扇环展开角度决定了判据的相移制动能力.仿真结果证明同步误差达到3ms时新判据能可靠制动,同时还能兼顾算法的灵敏度和电流互感器饱和时的安全性.
동보오차재차동보호중표현위상이,동보오차인기적안전성문제가이용차동보호적상이제동능력묘술.본문수선분석료전통비솔제동판거적상이제동능력,발현획취량호적상이제동능력필수희생산법적령민도.위료괄응약동보배경,본문제출료일충신적차동보호판거,신판거분별종폭치화상각량개방면독립형성제동약속,종이가이합병해결전류호감기화동보오차인기적불평형전류문제.신판거적제동구재ρ평면상정현선배형상,선배내경결정료판거적령민도,선배전개각도결정료판거적상이제동능력.방진결과증명동보오차체도3ms시신판거능가고제동,동시환능겸고산법적령민도화전류호감기포화시적안전성.
Synchronization errors lead to phase shifts and the phase shift restraint capacities could describe security characteristics of differential protections caused by synchronization errors. The phase shift restraint capacity of the traditional percentage differential protection gets better when the restraint coefficient increases, with the cost of the sensitivity depression to the internal faults. The paper proposes a new differential criterion whose restraint area inρrho plane is a sector-ring defined by the radius setting of the inner restraintcircle and the open angle setting in the unit circle. The radius setting controls the limits to magnitude errors and determines the sensitivity of protection during internal faults. The angle setting controls the amount of tolerance to phase angle errors and determines the phase shift restraint capacity of the protection independently. Simulation results show the new protection could resist 3ms time shift and has good sensitivity to inner slight faults and fine capability against current transformer saturation.