Abstract: An exemplary transformer includes an exciter unit (EU) and a compensating voltage unit (CVU). The EU including a three-phase transformer with shunt Y-connected primary windings. The CVU includes plural series-connected secondary windings having one secondary winding from each phase of the EU, and plural load tap changers. Each load tap changer is associated with a group of secondary windings that includes one secondary winding from each phase of the EU. Each secondary winding in a group of secondary windings is located at a same distance from an associated primary winding of the EU. All secondary windings, sub-windings between two consecutive taps, and primary windings have similar heights. Sub-windings may or may not be interleaved. Each load tap changer can vary an effective number of turns of the associated group of secondary windings by connecting to one of plural taps associated with each secondary winding according to a selected operating point.

Abstract: A system. The system includes a processor, a first module, a second module and a third module. The first module is communicably connected to the processor and is configured for calculating a q-axis voltage component and a d-axis voltage component. The second module is communicably connected to the processor and is configured for determining a voltage angle relative to the q-axis. The third module is communicably connected to the processor and is configured for (1) comparing the determined voltage angle to a predetermined value, (2) outputting the determined voltage angle if the determined voltage angle is less than the predetermined value, and (3) outputting the predetermined value if the predetermined value is less than the determined voltage angle.

Abstract: A system. The system includes a processor, a first module, a second module and a third module. The first module is communicably connected to the processor and is configured for calculating a q-axis voltage component and a d-axis voltage component. The second module is communicably connected to the processor and is configured for determining a voltage angle relative to the q-axis. The third module is communicably connected to the processor and is configured for (1) comparing the determined voltage angle to a predetermined value, (2) outputting the determined voltage angle if the determined voltage angle is less than the predetermined value, and (3) outputting the predetermined value if the predetermined value is less than the determined voltage angle.

Abstract: A control and regulation system for use with a harmonic neutralization frequency changer system. In the generalized frequency changer system, a direct converter frequency changer is used to convert bulk power, but unwanted harmonics are introduced. Input and output power distortion is monitored by a control system, and groups of high performance inverters inject shunt/series harmonic currents/voltages into a specially designed transformer to neutralize the power distortion to a specific acceptable level. Two control strategies are used including one that is based on discrete narrow band harmonic regulation and another that is based on wide band harmonic control. Each of these control strategies can be used at the input and/or output of the frequency changer and can be injected using shunt-current and series-voltage schemes.

Abstract: A series-compensating power flow transformer implements power flow control in a transmission line of an n-phase power transmission system, where each phase of the power transmission system has a transmission voltage. The transformer has n primary windings, where each primary winding is on a core and receives the transmission voltage of a respective one of the phases of the power transmission system. The transformer also has n secondary windings on the core of each primary winding for a total of n2 secondary windings. Each secondary winding has a voltage induced thereon by the corresponding primary winding, and one secondary winding from each core is assigned to each phase. For each phase, the secondary windings assigned to the phase are coupled in series for summing the induced voltages formed thereon, where the summed voltage is a compensating voltage for the phase.

Abstract: A power flow transformer implements power flow control in a transmission line of an n-phase power transmission system, where each phase of the power transmission system has a transmission voltage. The transformer has n secondary windings, where each secondary winding is on a core. The transformer also has n primary windings on the core of each secondary winding for a total of n2 primary windings, where one primary winding from each core is assigned to each phase. For each phase, the primary windings assigned to the phase are coupled in series, and the in-series primary windings receive the transmission voltage of the respective phase of the power transmission system. For each core, each primary winding thereon induces a voltage in the secondary thereon. The induced voltages are summed by the secondary to result in a summed induced voltage. Such summed induced voltage is a compensating voltage for a respective phase.

Abstract: A limited-angle power flow transformer implements power flow control in a transmission line of an n-phase power transmission system, where each phase of the power transmission system has a transmission voltage. The transformer has n primary windings, where each primary winding is on a core and receives the transmission voltage of a respective one of the phases of the power transmission system. The transformer also has m secondary windings on the core of each primary winding for a total of m*n secondary windings, where m is less than n. Each secondary winding has a voltage induced thereon by the corresponding primary winding. For each phase, m secondary windings are assigned to the phase. Each assigned secondary winding for the phase is from a different core. For all phases, the secondary windings are assigned from the cores in a balanced manner. For each phase, the secondary windings assigned to the phase are coupled in series for summing the induced voltages formed thereon.

Abstract: A shunt compensating power flow transformer implements power flow control in a transmission line of an n-phase power transmission system, where each phase of the power transmission system has a transmission voltage. The transformer has n primary windings, where each primary winding is on a core and receives the transmission voltage of a respective one of the phases of the power transmission system. The transformer also has n secondary windings on the core of each primary winding for a total of n2 secondary windings, where each secondary winding has a voltage induced thereon by the corresponding primary winding. One secondary winding from each core is assigned to each phase. For each phase, the secondary windings assigned to the phase are coupled in series for summing the induced voltages formed thereon.