Abstract: A method for compensating self-induced voltage variations includes computing a first reactive power value (Q1), obtaining a voltage value at a point of interconnection (POI) between at least one power source and a power grid, comparing the voltage value with one or more pre-defined voltage limits, computing at least one compensation factor (CF) corresponding to at least one portion of the first reactive power value (Q1) based on an output of the comparison between the voltage value and the one or more pre-defined voltage limits, computing a second reactive power value (Q2) as a function of the at least one portion of the first reactive power value (Q1) and the at least one CF, generating a reactive power compensation command based on the computed second reactive power value (Q2), and transmitting the reactive power compensation command to a power converter.

Abstract: A power distribution system for providing a desired value of voltage regulation is presented. The system includes at least one power source, at least one sink, a distribution feeder configured to couple the at least one power source to the at least one sink. The system includes a plurality of modular voltage regulation units coupled to the distribution feeder, where each of the plurality of modular voltage regulation units includes a transformer including a primary winding having a first end and a second end and a secondary winding having a first end and a second end; and at least one switch coupled to the primary winding of the transformer, where the first end of the secondary winding is coupled to at least one of the first and second ends of the primary winding via the at least one switch. A method of operating a power distribution system is also presented.

Abstract: An electric power system includes an OLTC transformer including a plurality of primary and secondary windings inductively coupled to each other. The electric power system includes at least one on-load tap changer coupled to at least one of the primary and secondary windings that is selectively configurable to regulate the portion of the primary and secondary windings inductively coupled to each other. The electric power system also includes a plurality of buses coupled to the transformer and are positioned downstream therefrom. The electric power system further includes at least one processor coupled to the tap changer configured to regulate a voltage bandwidth of the tap changer as a function of estimated voltage values of at least one bus as estimated based on a priori values of power/current transmitted through each bus. The a priori values are substantially based on measured power/current transmission through the on-load tap changer.

Abstract: An electric power system includes an OLTC transformer including a plurality of primary and secondary windings inductively coupled to each other. The electric power system includes at least one on-load tap changer coupled to at least one of the primary and secondary windings that is selectively configurable to regulate the portion of the primary and secondary windings inductively coupled to each other. The electric power system also includes a plurality of buses coupled to the transformer and are positioned downstream therefrom. The electric power system further includes at least one processor coupled to the tap changer configured to regulate a voltage bandwidth of the tap changer as a function of estimated voltage values of at least one bus as estimated based on a priori values of power/current transmitted through each bus. The a priori values are substantially based on measured power/current transmission through the on-load tap changer.

Abstract: A power distribution system for providing a desired value of voltage regulation is presented. The system includes at least one power source, at least one sink, a distribution feeder configured to couple the at least one power source to the at least one sink. The system includes a plurality of modular voltage regulation units coupled to the distribution feeder, where each of the plurality of modular voltage regulation units includes a transformer including a primary winding having a first end and a second end and a secondary winding having a first end and a second end; and at least one switch coupled to the primary winding of the transformer, where the first end of the secondary winding is coupled to at least one of the first and second ends of the primary winding via the at least one switch. A method of operating a power distribution system is also presented.

Abstract: An electric power system including an on-load tap changing (OLTC) transformer is provided. The OLTC transformer includes a primary winding and a secondary winding. A portion of the at least one primary winding and at least one of the secondary windings are inductively coupled to each other. Further, the electric power system includes at least one on-load tap changer coupled to the at least one primary winding or the at least one secondary winding of the OLTC transformer. The on-load tap changer is configured to regulate the portion of the at least one primary winding or the at least one secondary winding that are inductively coupled to each other. Furthermore, the system includes at least one controller coupled to the on-load tap changer. The controller is configured to determine a permissible voltage range defined by a bandwidth around a voltage set-point at the at least one on-load tap changer, where the bandwidth is a function of one or more electrical network states.

Abstract: A system for operating an on-load tap changer (OLTC) includes a plurality of legs that include mechanical switches. At least one leg switches from a first to a second tap of the OLTC on receipt of a tap change signal. At least one mechanical switch is activated to establish an electrical connection between one of the first and the second tap and a power terminal of the OLTC. Further, the system includes semiconductor switches that are parallel to the mechanical switches and when activated electrically couple one of the first and the second tap and the power terminal. The system includes a processing unit that selectively activates and deactivates the mechanical and semiconductor switches in such a way that electrical contact is maintained between at least one of the taps and the power terminal during the transition of at least one leg from the first tap to the second tap.

Abstract: A method of switching taps of an on-load tap changer includes providing a main finger, a first side finger including a first solid state switch and a second side finger including a second solid state switch. The main finger, the first side finger and the second side finger are utilized to provide a connection between the taps and a power terminal of the on-load tap changer. The method also includes triggering the on-load tap changer to shift the fingers from a first tap to a second tap of the on-load tap changer when a tap change signal is received and utilizing the first solid state switch and the second solid state switch to commutate a current during the tap change operation.

Abstract: A system for online filtering of photovoltaic (PV) output signals includes a programmable filter that is programmed to decompose measured PV output power into an estimated low-frequency signal component, based substantially on movement of the sun and an estimated high-frequency signal component, based substantially on cloud shading. An open loop controller generates a reactive power compensation signal based on at least one of the low-frequency signal component and the high-frequency signal component. The low-frequency signal component is defined by a positive portion of a sine curve that is based substantially on movement of the sun.

Abstract: An electric power system includes an on-load tap changing (OLTC) transformer. The transformer includes a plurality of primary windings and a plurality of secondary windings. At least a portion of one of the primary windings and the secondary windings are inductively coupled to each other. The system also includes at least one on-load tap changer coupled to at least one of the primary windings and the secondary windings. The on-load tap changer is selectively configurable to regulate the portion of at least one of the primary windings and the secondary windings inductively coupled to each other. The system further includes at least one processor coupled to the on-load tap changer. The processor is configured to adaptively regulate a voltage set-point of the on-load tap changer as a function of an adaptive OLTC transformer power flow dependent voltage set-point characteristic.

Abstract: A method for compensating self-induced voltage variations includes computing a first reactive power value (Q1), obtaining a voltage value at a point of interconnection (POI) between at least one power source and a power grid, comparing the voltage value with one or more pre-defined voltage limits, computing at least one compensation factor (CF) corresponding to at least one portion of the first reactive power value (Q1) based on an output of the comparison between the voltage value and the one or more pre-defined voltage limits, computing a second reactive power value (Q2) as a function of the at least one portion of the first reactive power value (Q1) and the at least one CF, generating a reactive power compensation command based on the computed second reactive power value (Q2), and transmitting the reactive power compensation command to a power converter.

Abstract: A system for online filtering of photovoltaic (PV) output signals includes a programmable filter that is programmed to decompose measured PV output power into an estimated low-frequency signal component, based substantially on movement of the sun and an estimated high-frequency signal component, based substantially on cloud shading. An open loop controller generates a reactive power compensation signal based on at least one of the low-frequency signal component and the high-frequency signal component. The low-frequency signal component is defined by a positive portion of a sine curve that is based substantially on movement of the sun.

Abstract: A method of switching taps of an on-load tap changer includes providing a main finger, a first side finger including a first solid state switch and a second side finger including a second solid state switch. The main finger, the first side finger and the second side finger are utilized to provide a connection between the taps and a power terminal of the on-load tap changer. The method also includes triggering the on-load tap changer to shift the fingers from a first tap to a second tap of the on-load tap changer when a tap change signal is received and utilizing the first solid state switch and the second solid state switch to commutate a current during the tap change operation.

Abstract: A system for operating an on-load tap changer (OLTC) includes a plurality of legs that include mechanical switches. At least one leg switches from a first to a second tap of the OLTC on receipt of a tap change signal. At least one mechanical switch is activated to establish an electrical connection between one of the first and the second tap and a power terminal of the OLTC. Further, the system includes semiconductor switches that are parallel to the mechanical switches and when activated electrically couple one of the first and the second tap and the power terminal. The system includes a processing unit that selectively activates and deactivates the mechanical and semiconductor switches in such a way that electrical contact is maintained between at least one of the taps and the power terminal during the transition of at least one leg from the first tap to the second tap.

Abstract: An electric power system includes an on-load tap changing (OLTC) transformer. The transformer includes a plurality of primary windings and a plurality of secondary windings. At least a portion of one of the primary windings and the secondary windings are inductively coupled to each other. The system also includes at least one on-load tap changer coupled to at least one of the primary windings and the secondary windings. The on-load tap changer is selectively configurable to regulate the portion of at least one of the primary windings and the secondary windings inductively coupled to each other. The system further includes at least one processor coupled to the on-load tap changer. The processor is configured to adaptively regulate a voltage set-point of the on-load tap changer as a function of an adaptive OLTC transformer power flow dependent voltage set-point characteristic.

Abstract: A method of switching taps by an on-load tap changer includes providing at least two fingers each comprising an impedance and a mechanical switch. When first and second mechanical switches of the first and second fingers are closed, they provide a connection between the first and second impedances of the first and second fingers and a power terminal of the on-load tap changer. The on-load tap changer is triggered to shift at least one of the fingers from a first tap to a second tap of the on-load tap changer when a tap change signal is received. A solid state switch connected between the first and second impedances is switched on to commutate a current from the first finger to the second finger during the tap change operation.