Abstract: Flexible AC transmission system (FACTS) enabling distributed controls is a requirement for power transmission and distribution, to improve line balancing and distribution efficiency. These FACTS devices are electronic circuits that vary in the type of services they provide. All FACTS devices have internal circuitry to handle fault currents. Most of these circuits are unique in design for each manufacturer, which make these FACTS devices non-modular, non-interchangeable, expensive and heavy. One of the most versatile FACTS device is the static synchronous series compensator (SSSC), which is used to inject impedance into the transmission lines to change the power flow characteristics. The addition of integrated fault current handling circuitry makes the SSSC and similar FACTS devices unwieldy, heavy, and not a viable solution for distributed control. What is disclosed are modifications to FACTS devices that move the fault current protection external to the FACTS device and make them modular and re-usable.

Abstract: In an impedance injection module in which multiple converter units are placed in series to realize a high level of impedance injection, switches, preferably vacuum interrupters, are connected to short the input and the output terminals of each individual unit. Unlike the fault-protecting switch across the entire module, these switches at the individual converter unit level serve several purposes, overload and surge protection of a unit, insertion loss minimization of an idle unit when the required impedance injection is small, and electrically removing a defective injection unit from the power flow to increase the overall reliability of the impedance injection module in the face of the failure of one unit or a few units. For more rapid response, particularly in response to faults, the vacuum interrupter at the unit level may be accompanied by an SCR switch in parallel with it.

Abstract: In prior art grid systems, power-line control is done by substation based large systems that use high-voltage (HV) circuits to get injectable impedance waveforms that can create oscillations on the HV power lines. Intelligent impedance injection modules (IIMs) are currently being proposed for interactive power line control and line balancing. These IIMs distributed over the high-voltage lines or installed on mobile platforms and connected to the HV power lines locally generate and inject waveforms in an intelligent fashion to provide interactive response capability to commands from utility for power line control.

Abstract: A modular liquid cooling block is described for cooling high current devices deployed in power flow control systems. The liquid cooling blocks may have separate shower heads which may be configured for direct impingement, indirect impingement, or parallel flow cooling configurations. Voltage isolation of liquid cooling blocks from an enclosure of the power flow control system and from associated equipment enables serial or parallel connected power flow control units to inject substantial reactive power that may be configurable into a power transmission line. Associated power flow control systems are monitored for temperature, flow rate and pressure gradient. Redundant pumps and fan radiators contribute to reliable operation. Automatic shutdown and alarm may be provided.

Abstract: A power supply system is operable to harvest power at low and high line currents. A current transformer is arranged to couple to a power transmission line. A current sensor which may be a Rogowski coil is arranged to couple to the power transmission line. Branches of power supply circuitry are connected to a plurality of secondary windings of the current transformer. A control circuit selects one of the branches of power supply circuitry, depending on sensed magnitude of line current, to provide electrical power to an output capacitor. Sufficient stored energy is also provided for performing a backup of operating parameters when the line current reduces to zero.

Abstract: A system enabling localized intelligent control with communication and coordination at local subsections of a power grid with information transfer to utility for supervisory control is disclosed. The disclosure extends the control and communication capability within, at the edge, and outside the edge of the power grid using intelligent and self-aware FACTS devices. Aspects of the disclosure enable control of a distribution network, energy storage systems and generation sources as an integrated system allowing optimization of power grid operation from generation to distribution. This control capability further enables a supervisory utility to implement and manage policy issues, such as standard compliance, carbon emission reduction, right-of-way management, and conformance to environmental regulations, such as EMI compliance, noise reduction, etc. This also allows the supervisory utility to optimize energy cost, network reliability, and asset utilization and life.

Abstract: A liquid cooling static synchronous series compensator (SSSC) system has inverter valve modules, inverter valve units and liquid cooling blocks. Liquid cooling blocks may be configured to provide a jetted flow, a parallel flow or an individualized flow, within an enclosed fluid chamber, for cooling inverter valve units. Liquid cooling blocks may have voltage isolation.

Abstract: An impedance injection unit (IIU) system is coupled to a high-voltage (HV) transmission line. The IIUs are activated in sequences of activation in successive time periods. This injects an impedance waveform onto the HV transmission line. The ordering of IIUs in the sequences of activation is repeatedly changed in successive time periods. This equalizes electrical stress across the IIUs used, leading to overall improvement in IIU system lifetimes.

Abstract: Disclosed is a reactance-injecting module and its method of use to balance the currents among the phases of polyphase electric power transmission lines or to manage power flow among alternate paths, where the reactance-injecting module has high-speed, dedicated communication links to enable the immediate removal or reduction of injected reactance from all phases of a phase balancing cluster when a fault is detected on any one of the multiple phases. The reactance-injecting module may communicate information on a detected fault to the other reactance-injecting modules of the phase balancing cluster within 10 microseconds after the fault is detected to allow the phase balancing cluster to eliminate injected reactance from all phases within a time that is short compared to a cycle of the alternating current, such as 1 millisecond after the fault is detected. This provides extremely fast neutralization of injected reactance to minimize interference with fault localization analyses.

Abstract: A system for managing power delivery and power flow in a distribution grid having grid forming capability is disclosed. The system includes a connect-disconnect switches operable to connect a power transmission grid to and disconnect the power transmission grid from the distribution grid. The distribution grid includes renewable energy generators and a number of loads. The system further includes a full bridge shunt inverter system connected to the distribution grid. The full bridge shunt inverter system includes a four-quadrant DC-to-AC inverter and at least a battery for power storage and operable as a power source for grid formation. The system further includes a pair of active filters connected in series on the distribution grid. The full bridge shunt inverter system is connected to the distribution grid at a node between the active filters to enable impedance adjustment for managing and controlling the power flow in the distribution grid.

Abstract: A flexible alternating current transmission system (FACTS)-based shunt system is described for use in a hierarchy in a high-voltage or medium-voltage power grid. The shunt system includes a FACTS-based shunt device, a communication link, and a shunt controller. A hierarchy in the power grid includes a supervisory utility communicably coupled to localized intelligence centers (LINCs). Each LINC is communicably coupled to one or more impedance injection modules (IIMs) that are coupled to the power grid. The hierarchy has an optimization engine. The shunt controller, of the shunt system, is to communicate and cooperate with one or more of the LINCs in the hierarchy. The shunt controller is to operate the FACTS-based shunt device in accordance with such communication and cooperation with the LINCs, to provide voltage stability to the power grid through hierarchical control according to the supervisory utility, the LINCs and the optimization engine.

Abstract: A control module controls impedance injection units (IIUs) to form multiple connection configurations in sequence. Each connection configuration has one IIU, or multiple IIUs in series, parallel or combination of series and parallel. The connection configurations of IIUs are coupled to a high-voltage transmission line. The control module and the IIUs generate rectangular impedance injection waveforms. When the waveforms are combined and injected to the high-voltage transmission line, this produces a pseudo-sinusoidal waveform.

Abstract: An apparatus for injecting impedance into a high voltage (HV) transmission line is disclosed. The apparatus comprises a plurality of modular flexible alternating current transmission systems (FACTS) based impedance injection units (IIUs), each modular FACTS based IIU without fault current protection. The apparatus further comprises a fault current protection module external to the modular FACTS based IIUs. The fault current protection module is coupled to the modular FACTS based IIUs to provide fault current protection to the modular FACTS based IIUs.

Abstract: A system has grid forming capability. A connect-disconnect switch is connectable to a power transmission grid and connectable to a distribution grid that may have renewable energy generation sources and loads. A shunt inverter system comprising a 4-quadrant DC-to-AC inverter and a battery power source is connectable to the distribution grid. A controller controls the connect-disconnect switch to connect and disconnect the distribution grid from the power transmission grid, or disconnect a first segment of the distribution grid from a second segment of the distribution grid. The controller operates the shunt inverter system to provide power factor correction to the distribution grid under normal operation. The controller operates the shunt inverter system with switching and current control instructions to enable grid forming and sustaining of continued operation of the distribution grid.

Abstract: A system architecture and method for enabling hierarchical intelligent control with appropriate-speed communication and coordination of control using intelligent distributed impedance/voltage injection modules, local intelligence centers, other actuator devices and miscellaneous FACTS coupled actuator devices is disclosed. Information transfer to a supervisory utility control is enabled for responding to integral power system disturbances, system modelling and optimization. By extending the control and communication capability to the edge of the HV power grid, control of the distribution network through FACTS based Demand response units is also enabled.

Abstract: A passive cooling topology and a manufacturing method are described for a transformer to achieve improved power density at a light weight. No fans or cooling liquids are required. Vertical planar faces are used for the central core element, the primary and secondary windings, the outer core element, and a finned heat sink. The primary flow for thermal cooling is radial, through the vertical planar faces. The transformer may be configured to float at the potential of a high voltage transmission line, leading to improved thermal characteristics. Eddy currents are reduced using repeating air gaps in the central core, and a continuously transposed cable comprising multiple strands per turn in the secondary winding. Air pockets in the windings are eliminated using a potting resin and vacuum pressure impregnation (VPI).

Abstract: A voltage source converter has a first inverter valve unit that has a first terminal and a second terminal, and a second inverter valve unit that has a first terminal and a second terminal. The first inverter valve unit and the second inverter valve unit are connectedly arranged in parallel. The first inverter valve unit and the second inverter valve unit are self-balancing through equal capacitance and parallel connection of the first inverter valve unit and the second valve unit.

Abstract: A modular liquid cooling block is described for cooling high current devices deployed in power flow control systems. The liquid cooling blocks may have separate shower heads which may be configured for direct impingement, indirect impingement, or parallel flow cooling configurations. Voltage isolation of liquid cooling blocks from an enclosure of the power flow control system and from associated equipment enables serial or parallel connected power flow control units to inject substantial reactive power that may be configurable into a power transmission line. Associated power flow control systems are monitored for temperature, flow rate and pressure gradient. Redundant pumps and fan radiators contribute to reliable operation. Automatic shutdown and alarm may be provided.

Abstract: A filter network is insertable into a power transmission line, to handle disturbances in the power transmission line. A first circuit has an RC network in parallel with a surge arrestor, to bypass high frequency disturbances of the power transmission line. A second circuit has inductors for carrying low-frequency power to and from impedance injection units.

Abstract: The presence of injected DC has harmful consequences for a power grid system. A piecewise sinusoidal ripple voltage wave at the line-frequency that rides on the main capacitor bank of the power converter is observed. This observation leads to a new detection method and mitigation method. A two-stage control circuit is added to the operation of a power converter that controls power line impedance in order to mitigate the injected DC and to block DC circulation. This control computes a correction angle to adjust the timing of generated pulsed square waves to counter-balance the ripple. A functional solution and the results of experiments are presented. Furthermore, an extraction method and three elimination methods for this ripple component are presented to allow dissipation of DC energy through heat and/or electronic magnetic wave, or to allow transformation of this energy into usable power that is fed back into the power grid.