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DETERMINING ELECTRICAL FAULTS ON UNDERGROUNDED POWER SYSTEMS USING DIRECTIONAL ELEMENT
DETERMINING ELECTRICAL FAULTS ON UNDERGROUNDED POWER SYSTEMS USING DIRECTIONAL ELEMENT
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机译:使用方向元素确定地下电力系统的电气故障
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摘要
The directional element, following enablement under selected input current conditions, calculates a zero sequence impedance, in response to values of zero sequence voltage and zero sequence current. The current value is selected between two possible values, one being the value from an associated current transformer, the other being the sum of the currents IA+IB+IC. The calculated zero sequence impedance is then compared against sensitive selected threshold values, established particularly for ungrounded systems. A forward fault indication is provided when the calculated zero sequence impedance is above a first established sensitive threshold value, and a reverse fault indication is provided when the calculated zero sequence impedance is below a second established sensitive threshold value.
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