System for detecting internal winding faults of a synchronous generator, computer program product and method
First Claim
1. A method for monitoring, including detecting, internal winding faults, especially inter-turn faults, of a synchronous generator, which synchronous generator comprises a winding for each phase of a power network, a terminal for each phase arranged on a terminal side of the synchronous generator, and connected to the respective winding, the terminals on the terminal side is connected to an electrical power network, and the synchronous generator is arranged to input power to the electrical power network by means of the terminals, the method comprising:
- measuring the voltage of each phase at the at least one each terminal and the current of each phase at the terminal,determining whether the synchronous generator suffers from an internal fault especially inter-turn faults in any of its phases, wherein the determining includes;
transforming the phase currents and the phase voltages into symmetric sequence currents and symmetric sequence voltages, respectively;
monitoring at least one of the following variables;
a negative sequence residual voltage;
a zero sequence residual voltage;
a negative sequence coupling impedance;
a zero sequence coupling impedance;
wherein each of the variables is calculated from symmetric sequence components and at least one generator specific impedance, anddetermining whether the synchronous generator suffers from a winding fault, or not, from the calculated at least one residual voltage or coupling impedance;
the method further comprising an additional internal fault detection step including analysing the rotor field winding current of the synchronous generator.
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Accused Products
Abstract
A system, method and computer program product for monitoring including detecting internal faults especially inter-turn faults of a synchronous generator and thus protecting the synchronous generator. The synchronous generator includes a winding for each phase of a power network, a terminal for each phase arranged on a terminal side of the synchronous generator, and connected to the respective winding, the terminals on the terminal side are connected to an electrical power network, and the synchronous generator is arranged to input power to the electrical power network by means of the terminals.
16 Citations
20 Claims
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1. A method for monitoring, including detecting, internal winding faults, especially inter-turn faults, of a synchronous generator, which synchronous generator comprises a winding for each phase of a power network, a terminal for each phase arranged on a terminal side of the synchronous generator, and connected to the respective winding, the terminals on the terminal side is connected to an electrical power network, and the synchronous generator is arranged to input power to the electrical power network by means of the terminals, the method comprising:
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measuring the voltage of each phase at the at least one each terminal and the current of each phase at the terminal, determining whether the synchronous generator suffers from an internal fault especially inter-turn faults in any of its phases, wherein the determining includes; transforming the phase currents and the phase voltages into symmetric sequence currents and symmetric sequence voltages, respectively; monitoring at least one of the following variables; a negative sequence residual voltage; a zero sequence residual voltage; a negative sequence coupling impedance; a zero sequence coupling impedance;
wherein each of the variables is calculated from symmetric sequence components and at least one generator specific impedance, anddetermining whether the synchronous generator suffers from a winding fault, or not, from the calculated at least one residual voltage or coupling impedance; the method further comprising an additional internal fault detection step including analysing the rotor field winding current of the synchronous generator. - View Dependent Claims (2, 3, 4, 5, 6, 7, 12, 13)
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8. A system for detecting internal winding faults of a synchronous generator, which synchronous generator comprises a winding for each phase of a power network, at least one terminal for each phase arranged on a terminal side of the synchronous generator, and connected to the respective winding, the terminals on the terminal side is connected to an electrical power network, and the synchronous generator is arranged to input power to the electrical power network by means of the terminals, the detecting system comprises
a measurement circuit arranged for receiving terminal phase voltages and terminal phase currents measurements; -
a mathematical transformation provider for transforming each phase voltages into symmetrical sequence voltage components and each phase currents into symmetrical sequence current components; and a winding fault determiner adapted to detect internal winding faults in the synchronous generator from the negative sequence components, or the zero sequence components, of the voltages and currents; the system further comprising an additional internal fault detector for analysing the rotor field winding current of the synchronous generator. - View Dependent Claims (9, 10, 11, 14, 15)
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16. A non-transitory computer readable medium storing a computer program product for determining an internal fault of a synchronous generator, which synchronous generator comprises a winding for each phase of a power network, a terminal for each phase being arranged on a terminal side of the synchronous generator, and connected to the respective winding, the terminals on the terminal side is connectable to an electrical power network, and the synchronous generator being arranged to input power to the electrical power network by means of the terminals, which computer program product when run on a computer that receives current and voltage measurements from measuring devices arranged at the phase terminals of a synchronous generator causes the computer to perform the following steps
transforming the measured phase currents and the measured phase voltages into symmetric sequence currents and symmetric sequence voltages, respectively; -
monitoring at least one of the following variables; a negative sequence residual voltage; a zero sequence residual voltage; a negative sequence coupling impedance; a zero sequence coupling impedance;
wherein each of the variables is calculated from symmetric sequence components and at least one generator specific impedance, anddetermining whether the synchronous generator suffers from a winding fault, or not, from the calculated at least one residual voltage or coupling impedance; the computer program product also causing the computer to perform an additional internal fault detection step including analysing the rotor field winding current of the synchronous generator. - View Dependent Claims (17, 18, 19, 20)
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Specification