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 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: A system and method using four switches connected in an H-bridge (full bridge) topology within a series-connected FACTS device is disclosed. System and method can be used to bypass a FACTS device. The switches in H-bridge are connected to an alternating current (AC) source allowing for various switching states, and enabling non-monitoring mode, local bypass monitoring mode, low-loss monitoring mode, and diagnostic mode of operation.

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 DC detection elimination method. Three DC elimination methods for this ripple component are disclosed to allow dissipation of DC energy through heat and/or electromagnetic wave, or to allow transformation of this energy into usable power that is fed back into the power grid.

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.

Abstract: A fastening system for securing and real-time monitoring of a bolted connection is described. An ultrasonic signal is used to measure time-of-flight in the bolt and calculate an effective length of the bolt. By comparing the calculated effective length against reference values, a loosened bolt may be detected, and a real-time decision can be made to initiate protective measures and/or make a report to a support system. The measuring subsystem can be configured to be electrically isolated, and the bolted connection may include a live electrical connection. The real-time monitoring can provide early warning of potential system failures across any system having bolted connections: this includes civil systems such as buildings and bridges, transportation devices such as trains and airplanes and automobiles, and power distribution systems.

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: An inverter device, an energy storage system comprising such an inverter device, and a method of controlling such an inverter device are provided. The inverter device has a split-phase, transformer-less configuration and is connectable between a battery and a power grid for transferring power in a bidirectional manner between said battery and said power grid. The inverter device further comprises: an inverter circuit comprising switching elements arranged in a multilevel clamped topology; and a control unit controlling said switching elements, wherein said control unit is configured to control said switching elements such that direct current (DC) power from said battery is transformed into alternating current (AC) power and supplied to said power grid during a discharging period, and AC power from said power grid is transformed into DC power and supplied to said battery during a charging period.

Abstract: An inverter device, an energy storage system comprising such an inverter device, and a method of controlling such an inverter device are provided. The inverter device has a split-phase, transformer-less configuration and is connectable between a battery and a power grid for transferring power in a bidirectional manner between said battery and said power grid. The inverter device further comprises: an inverter circuit comprising switching elements arranged in a multilevel clamped topology; and a control unit controlling said switching elements, wherein said control unit is configured to control said switching elements such that direct current (DC) power from said battery is transformed into alternating current (AC) power and supplied to said power grid during a discharging period, and AC power from said power grid is transformed into DC power and supplied to said battery during a charging period.

Abstract: An inverter device, an energy storage system comprising such an inverter device, and a method of controlling such an inverter device are provided. The inverter device has a split-phase, transformer-less configuration and is connectable between a battery and a power grid for transferring power in a bidirectional manner between said battery and said power grid. The inverter device further comprises: an inverter circuit comprising switching elements arranged in a multilevel clamped topology; and a control unit controlling said switching elements, wherein said control unit is configured to control said switching elements such that direct current (DC) power from said battery is transformed into alternating current (AC) power and supplied to said power grid during a discharging period, and AC power from said power grid is transformed into DC power and supplied to said battery during a charging period.