摘要:
The invention concerns a method and computer program product for determining the direction of fault in an electrical power system as well as to a fault handling device. In the fault handling device the voltage at a measurement node of the power system is measured, the phase (φPF) of this voltage (VPF) before a fault is stored, the phase (φF) of this voltage (VF) at the end of a time interval (TI) following directly after a detected fault is determined, a phase offset (φO) is determined as the difference between the phase (φPF) of the measured voltage (VPF) before the fault and the phase (φF) of the measured voltage (VF) at the end of the time interval (TI) and the phase (φF) of the measured voltage (VF) after the detection of the fault is adjusted with the phase offset (φO). Thereafter the adjusted measured voltage is used in determining the direction of fault in relation to the measurement node.
摘要:
The invention concerns a method and computer program product for determining the direction of fault in an electrical power system as well as to a fault handling device. In the fault handling device the voltage at a measurement node of the power system is measured, the phase (φPF) of this voltage (VPF) before a fault is stored, the phase (φF) of this voltage (VF) at the end of a time interval (TI) following directly after a detected fault is determined, a phase offset (φO) is determined as the difference between the phase (φPF) of the measured voltage (VPF) before the fault and the phase (φF) of the measured voltage (VF) at the end of the time interval (TI) and the phase (φF) of the measured voltage (VF) after the detection of the fault is adjusted with the phase offset (φO). Thereafter the adjusted measured voltage is used in determining the direction of fault in relation to the measurement node.
摘要:
A method, device and computer program product for determining at least one property of a current (Ip) running through the primary winding of a transformer operating in saturation using an unreliable detected current (Is) running through the secondary winding of the transformer. According to the invention a first reliable extreme point (EP1) of a cycle of the current in the secondary winding is detected and compared with an absolute time reference. Based on the comparison a first property of the current running through the primary winding in the form of the phase angle is then determined.
摘要:
A load compensation method for phase-to-ground loops in distance protection. A first reactive reach is estimated assuming zero fault resistance or with a positive sequence current. A second reactive reach is estimated with a zero sequence current. A third reactive reach is estimated with a negative sequence current. An import or export condition is estimated. A fourth reactive reach for import or export condition is estimated based on the first, second and third reactive reach. A fault impedance is estimated based on the estimated fourth reactive reach.
摘要:
A load compensation method for phase-to-ground loops in distance protection. A first reactive reach is estimated assuming zero fault resistance or with a positive sequence current. A second reactive reach is estimated with a zero sequence current. A third reactive reach is estimated with a negative sequence current. An import or export condition is estimated. A fourth reactive reach for import or export condition is estimated based on the first, second and third reactive reach. A fault impedance is estimated based on the estimated fourth reactive reach.
摘要:
A method, device and computer program product for determining at least one property of a current (Ip) running through the primary winding of a transformer operating in saturation using an unreliable detected current (Is) running through the secondary winding of the transformer. According to the invention a first reliable extreme point (EP1) of a cycle of the current in the secondary winding is detected and compared with an absolute time reference. Based on the comparison a first property of the current running through the primary winding in the form of the phase angle is then determined.