Abstract: Provided is a renewable power generation plant, a computer program product and method of controlling a renewable power generation plant including a power converter for connecting the renewable power generation plant to a power transmission network; a circuit breaker arrangement between the power converter and the power transmission network including a circuit breaker for each phase of the renewable power generation plant; and a converter controller configured to generate control signals for the power converter and control signals for the circuit breaker arrangement; which method includes the steps of detecting the occurrence of a phase-to-ground fault event in one of the phases of the power transmission network; issuing control signals to the circuit breaker arrangement to keep the circuit breakers closed during the phase-to-ground event; and issuing control signals to the power converter to ride through the phase-to-ground fault event.

Abstract: Provided is a renewable power generation plant, a computer program product and method of controlling a renewable power generation plant including a power converter for connecting the renewable power generation plant to a power transmission network; a circuit breaker arrangement between the power converter and the power transmission network, including a circuit breaker for each phase of the renewable power generation plant; and a converter controller configured to generate control signals for the power converter and control signals for the circuit breaker arrangement; which method includes the steps of detecting the occurrence of a phase-to-ground fault event in one of the phases of the power transmission network; issuing control signals to the circuit breaker arrangement to keep the circuit breakers closed during the phase-to-ground event; and issuing control signals to the power converter to ride through the phase-to-ground fault event.

Abstract: A method, arrangement and computer program product for enhancing the reliability of wide area control in a power transmission system where the wide area control is performed in the power transmission system based on measurements of system data. The arrangement includes an estimating unit configured to generate estimated measurement values based on at least one control signal being sent into the system and a model of the system, where the estimated measurement values correspond to a set of actual measurement values that are provided by a number of measurement providing devices in the system. The arrangement also includes a control unit configured to replace, if one or more deviation condition associated with at least one actual measurement value is fulfilled, at least the actual measurement values of the set being associated with the one or more deviation condition with corresponding estimated measurement values.

Abstract: The invention provides improved control of a power transmission system having a first group of measurement units in a first geographical area providing a first set of phasors and a second group of measurement units in a second geographical area providing a second set of phasors, where the phasors in the sets are generated at the same instant in time. In this system the power control device includes a phasor aligning unit that time aligns the first and second sets of phasors and a control unit that compares each set of phasors with a corresponding phasor number threshold, determines that a first control condition is fulfilled if each phasor number threshold has been exceeded and enables the provision of a common signal if the first control condition is fulfilled. The common signal is based on the obtained phasors in the first and second sets.

Abstract: A method, device and computer program product for providing improved control of power or voltage oscillation damping in a power transmission system. The device includes a magnitude obtaining element configured to obtain an instantaneous magnitude of a signal representing a deviating oscillation in at least one element of the power transmission system, a slope investigating element configured to determine the rate of change of the signal, and a first processing block including an integrating element configured to integrate the instantaneous magnitudes with an integrating factor that is based on the determined rate of change. The first processing block is further configured to form a phase compensation angle based on the integrated instantaneous magnitude for use in a damping control signal generating unit in order to provide power or voltage oscillation damping of the system.

Abstract: The disclosure is related to a method, power control device and computer program product for evaluating accuracy of timing provided by time generating equipment in relation to wide area control in a power transmission system, where the wide area control is performed based on time stamped measurements of system data. The power control device can include a timing deviation handling unit that investigates timing used in relation to time based measurements, determines if the timing is reliable or not based on the investigation, and aborts wide area control if the timing is deemed unreliable.

Abstract: A method for controlling power flow within a DC power flow within a DC power transmission network includes two or more interconnected converter stations. The method includes the steps of: establishing a common feedback signal (Ud,common, ?d,common) to the converter stations, the common feedback signal (Ud,common, ?d,common) being based on an overall voltage level in the DC transmission, power network; providing, in the converter stations, a control signal (S1, S2, S3, S4) based on the common feedback signal (Ud,common) and a drooped error signal (Pe,droop, Ue,droop); and controlling the power flow within the DC power transmission network towards set operating points (Udref, PCCref) by using the control signal (S1, S2, S3, S4). A control device and computer program product is also described.

Abstract: A method and controller are provided for the compensation of time delays in remote feedback signals in power system control. The method includes converting the time delay into a phase shift and calculating four compensation angles from the phase shift. The optimal compensation angle is determined and applied to the remote feedback signals. A technique of equipping a controller with a global clock is also disclosed.

Abstract: A method for controlling power flow within a DC power flow within a DC power transmission network includes two or more interconnected converter stations. The method includes the steps of: establishing a common feedback signal (Ud,common, ?d,common) to the converter stations, the common feedback signal (Ud,common, ?d,common) being based on an overall voltage level in the DC transmission, power network; providing, in the converter stations, a control signal (S1, S2, S3, S4) based on the common feedback signal (Ud,common) and a drooped error signal (Pe, droop, Ue, droop); and controlling the power flow within the DC power transmission network towards set operating points (Udref, PCCref) by using the control signal (S1, S2, S3, S4). A control device and computer program product is also described.

Abstract: The invention provides improved control of a power transmission system having a first group of measurement units in a first geographical area providing a first set of phasors and a second group of measurement units in a second geographical area providing a second set of phasors, where the phasors in the sets are generated at the same instant in time. In this system the power control device includes a phasor aligning unit that time aligns the first and second sets of phasors and a control unit that compares each set of phasors with a corresponding phasor number threshold, determines that a first control condition is fulfilled if each phasor number threshold has been exceeded and enables the provision of a common signal if the first control condition is fulfilled. The common signal is based on the obtained phasors in the first and second sets.

Abstract: A method, arrangement and computer program product for enhancing the reliability of wide area control in a power transmission system where the wide area control is performed in the power transmission system based on measurements of system data. The arrangement includes an estimating unit configured to generate estimated measurement values based on at least one control signal being sent into the system and a model of the system, where the estimated measurement values correspond to a set of actual measurement values that are provided by a number of measurement providing devices in the system. The arrangement also includes a control unit configured to replace, if one or more deviation condition associated with at least one actual measurement value is fulfilled, at least the actual measurement values of the set being associated with the one or more deviation condition with corresponding estimated measurement values.

Abstract: A method, device and computer program product for providing improved control of power or voltage oscillation damping in a power transmission system. The device includes a magnitude obtaining element configured to obtain an instantaneous magnitude of a signal representing a deviating oscillation in at least one element of the power transmission system, a slope investigating element configured to determine the rate of change of the signal, and a first processing block including an integrating element configured to integrate the instantaneous magnitudes with an integrating factor that is based on the determined rate of change. The first processing block is further configured to form a phase compensation angle based on the integrated instantaneous magnitude for use in a damping control signal generating unit in order to provide power or voltage oscillation damping of the system.

Abstract: A method and controller are provided for the compensation of time delays in remote feedback signals in power system control. The method includes converting the time delay into a phase shift and calculating four compensation angles from the phase shift. The optimal compensation angle is determined and applied to the remote feedback signals. A technique of equipping a controller with a global clock is also disclosed.

Abstract: The disclosure is related to a method, power control device and computer program product for evaluating accuracy of timing provided by time generating equipment in relation to wide area control in a power transmission system, where the wide area control is performed based on time stamped measurements of system data. The power control device can include a timing deviation handling unit that investigates timing used in relation to time based measurements, determines if the timing is reliable or not based on the investigation, and aborts wide area control if the timing is deemed unreliable.