A method of operating a power generating system for a wind turbine connected to an electrical grid, the power generating system comprising a power generator, a converter, a transformer and a tap changer, the method comprising; monitoring a signal for detecting an over-voltage condition in the electrical grid which requires a reduction in the output voltage from the power generating system; initiating a convertor response mode configured to provide at least part of the required voltage reduction; and initiating a transformer response mode configured to provide at least part of the required voltage reduction; wherein the transformer response mode comprises operating the tap changer to adjust the output voltage from the power generating system.

A system contains a double fed induction machine having a stator and a rotor, a fly wheel coupled to the rotor, and a control device for providing a rotor voltage and a rotor current to the rotor. The control device is connected to the rotor and the stator and is capable of generating the rotor voltage and rotor current in response to an electrical signal that is applied to the stator. The control device has a multilevel converter and a control unit for controlling the multilevel converter.

A modular system is described which can provide high frequency monitoring of power use and responsive control as well as enabling network connectivity for centralised monitoring and operation. One modular system consists of a communications bus, end caps, and a combination of the modules providing communications, power metering, relay control and battery backup. Each modular system can be configured with a combination of modular units as needed for the application. A combination of bus communication monitoring and tilt detection provides security against external tampering after installation.

A modular system is described which can provide high frequency monitoring of power use and responsive control as well as enabling network connectivity for centralised monitoring and operation. One modular system consists of a communications bus, end caps, and a combination of the modules providing communications, power metering, relay control and battery backup. Each modular system can be configured with a combination of modular units as needed for the application. A combination of bus communication monitoring and tilt detection provides security against external tampering after installation.

A system of surge suppressor units is connected at multiple locations on a power transmission and distribution grid to provide grid level protection against various disturbances before such disturbances can reach or affect facility level equipment. The surge suppressor units effectively prevent major voltage and current spikes from impacting the grid. In addition, the surge suppressor units include various integration features which provide diagnostic and remote reporting capabilities required by most utility operations. As such, the surge suppressor units protect grid level components from major events such as natural geomagnetic disturbances (solar flares), extreme electrical events (lightning) and human-generated events (EMPs) and cascading failures on the power grid.

A system of surge suppressor units is connected at multiple locations on a power transmission and distribution grid to provide grid level protection against various disturbances before such disturbances can reach or affect facility level equipment. The surge suppressor units effectively prevent major voltage and current spikes from impacting the grid. In addition, the surge suppressor units include various integration features which provide diagnostic and remote reporting capabilities required by most utility operations. As such, the surge suppressor units protect grid level components from major events such as natural geomagnetic disturbances (solar flares), extreme electrical events (lightning) and human-generated events (EMPs) and cascading failures on the power grid.

According to one embodiment, a voltage converting device includes a DC power source; an inverter generating AC power; an AC component detector configured to detect an AC component of current flowing through a first terminal or a second terminal of the inverter in the DC power source side; and a phase estimator configured to estimate a phase relation between a phase of voltage of the AC power and a phase of current of the AC power based on an amplitude of a specific frequency component contained in a first absolute value signal of the AC component. The AC power generated by the inverter is supplied to a loading device, and an impedance of the loading device at a fundamental of a driving frequency of the inverter is smaller than an impedance of the loading device at an odd-order harmonic of the driving frequency.

The present disclosure relates to a device of monitoring a reactive power compensation system to compensate reactive power, the device including a measurement unit configured to acquire voltage data, current data, and a phase angle from each constituent device, a power performance index calculation unit configured to calculate power performance index data including at least one of power factor data, flicker data, and harmonics data based on the acquired voltage data, current data, and phase angle, and a controller configured to analyze and evaluate the calculated power performance index data based on a preset situation.

The present disclosure relates to a device of monitoring a reactive power compensation system to compensate reactive power, the device including a measurement unit configured to acquire voltage data, current data, and a phase angle from each constituent device, a power performance index calculation unit configured to calculate power performance index data including at least one of power factor data, flicker data, and harmonics data based on the acquired voltage data, current data, and phase angle, and a controller configured to analyze and evaluate the calculated power performance index data based on a preset situation.

A var compensator circuit is provided. The var compensator circuit includes a gas tube switch and a reactive impedance. The gas tube switch is configured to be coupled to a transmission line. The transmission line is configured to deliver real power and reactive power to a load at an alternating current (AC) line voltage. The reactive impedance is configured to be coupled to the transmission line at the AC line voltage through the gas tube switch. The reactive impedance is configured to modify the reactive power configured to be delivered to the load.