Invention Application
WO2003036312A2 DIRECTIONAL ELEMENT TO DETERMINE FAULTS ON UNGROUNDED POWER SYSTEMS
审中-公开
使用方向元素确定地下电力系统的电气故障
- Patent Title: DIRECTIONAL ELEMENT TO DETERMINE FAULTS ON UNGROUNDED POWER SYSTEMS
- Patent Title (中): 使用方向元素确定地下电力系统的电气故障
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Application No.: PCT/US2002/034059Application Date: 2002-10-23
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Publication No.: WO2003036312A2Publication Date: 2003-05-01
- Inventor: ROBERTS, Jeffrey, B.
- Applicant: SCHWEITZER ENGINEERING LABORATORIES, INC.
- Applicant Address: 2350 Northeast Hopkins Court, Pullman, WA 99163 US
- Assignee: SCHWEITZER ENGINEERING LABORATORIES, INC.
- Current Assignee: SCHWEITZER ENGINEERING LABORATORIES, INC.
- Current Assignee Address: 2350 Northeast Hopkins Court, Pullman, WA 99163 US
- Agency: PUNTIGAM, Clark, A.
- Priority: US09/999,837 20011024
- Main IPC: G01R31/00
- IPC: G01R31/00
Abstract:
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 I A +I B +I C . 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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