Provided is a power management apparatus for controlling power distribution from a location that includes a storage battery and a current control type converter to another location that includes a storage battery, the power management apparatus including: a monitor unit that acquires a status of the storage battery at each location; a judgment unit that determines, based on the status of the storage battery at each location that has been acquired by the monitor unit, a duration of power distribution to a certain location, and one or more locations from which power is to be distributed to the certain location; and a control unit that controls each location serving as a distribution source such that power distribution is performed for the duration determined by the judgment unit.

In a multi-terminal DC power transmission system, a common control device is connected to a plurality of individual protective devices via a first communication network. Each of the individual protective devices is configured, when detecting change in current or voltage in a corresponding protection zone, to output a fault signal to the common control device via the first communication network and open the corresponding DC circuit breaker such that the corresponding protection zone is disconnected from the multi-terminal DC power grid and deenergized. The common control device estimates a fault occurrence zone where a fault occurs among a plurality of protection zones, based on a plurality of received fault signals. The common control device requests an individual protective device corresponding to a deenergized protection zone of the protection zones excluding the fault occurrence zone to reclose the DC circuit breaker such that the deenergized protection zone is restored.

A high voltage direct current power transmission series valve group control device, is used for regulating a series circuit having two or more valve groups provided with controllable power semiconductors respectively. Each valve group is provided with a current regulation unit and a voltage regulation unit. The current regulation unit controls a direct current current flowing through a valve group corresponding thereto, and the voltage regulation unit controls a voltage across two ends of a valve group corresponding thereto. One valve group is selected from the series valve group as a master control valve group, while the others are taken as slave control valve groups. The master control valve group selects a trigger angle output by the current regulation unit to control same, and the slave control valve group selects a trigger angle obtained after the trigger angle transmitted from the master control valve group and an output value of the voltage regulation unit pass through a subtractor to control same.

The present invention relates to a power management system (PMS) for multiple energy storage systems (ESS) that is for integrated management of the system having multiple ESS for controlling a frequency and having a hierarchical control structure. The PMS for ESS comprises: a plurality of ESS; a local management system (LMS) for managing one or more ESS of the plurality of ESS for each local unit; an ESS Controller (ESSC) for general management of the LMS, judging a state of the LMS and determining an output value of one or more ESS in the LMS, and transmitting the determined output value to the respective ESS; and a PMS for general management of the entire system comprising the plurality of ESS, the LMS and the ESSC, judging the state of the entire system and participating in a power grid frequency control market through a grid operator contract, controlling the output of the LMS, and adjusting a control parameter for output control.

A control circuit is provided, including first and second terminals for connection to an electrical network; a current transmission path extending between the first and second terminals, the current transmission path including first and second current transmission path portions, the first and second current transmission path portions being arranged to permit a current flowing, in use, between the first and second terminals and through the first current transmission path portion to bypass the second current transmission path portion and to permit a current flowing, in use, between the first and second terminals and through the second current transmission path portion to bypass the first current transmission path portion; and a controller configured to selectively remove the or each energy storage device from the respective current transmission path portion to cause current to flow from the electrical network through the current transmission path and the or each energy conversion element.

A method of clearing a fault in a high voltage DC electrical network, including power converters interconnected by a DC power transmission, comprising: detecting a fault in the DC power transmission and reconfiguring each power converter to a fault blocking mode drinving the DC fault current towards zero; locating the fault and isolating a faulty portion from a healthy remaining portion; reconfiguring one of the power converters designated as a re-energising power converter from the fault blocking to re-energise the healthy remaining portion; and detecting a rise in the voltage level in the healthy remaining portion above a threshold level and reconfiguring the remaining power converter connected with the healthy remaining portion from the fault blocking to the normal power transmission.

A loss optimization control method for modular multilevel converters (MMCs) under fault-tolerant control is disclosed. The method includes the following steps: when a fault of a SM in a MMC occurs, bypassing the faulty SM to achieve fault-tolerant control; suppressing the fundamental circulating current using a fundamental circulating current controller; respectively calculating the loss of each SM in faulty arms and healthy arms by using loss expressions of different switching tubes in SMs of the MMC; aiming at the loss imbalance between the arms of the MMC, taking the loss of a healthy SM as the reference, adjusting the period of capacitor voltage sorting control in the faulty SMs, achieving the loss control over the working SMs in the faulty SMs, and finally achieving the loss balance of each SM in the faulty arms and the healthy arms. Compared with the conventional methods, the proposed method is easier to implement and does not increase the construction cost of MMCs.

The present disclosure includes methods and apparatus for HVDC power distribution. A control apparatus is described for controlling a frequency set-point for a first AC network electrically connected to a first HVDC station to regulate active power. The controller has a frequency controller operable in a first mode of operation to determine a frequency set-point (Fref) for the first AC network based on a measured DC voltage at the first HVDC station. A disturbance detector is configured to monitor the measured value of DC voltage at the first HVDC station (VDC1) for a predetermined characteristic indicative that a variation in measured DC voltage does correspond to a known modulation applied to the DC voltage by a second HVDC station. The frequency controller is configured to determine the frequency set-point (Fref) for the first AC network based on a measured value of DC voltage (VDC1) if said predetermined characteristic is detected, and to control the frequency set-point to a predetermined default frequency if said predetermined characteristic is not detected.

A grid-forming wind turbine control method for a diode rectifier unit-based offshore wind power transmission system. A control system for controlling a grid-side converter has a three-layered structure, where a first layer is a combination of an active power controller and a reactive power controller; a second layer is a voltage controller; and a third layer is a current controller. The actual reactive power is represented by a per-unit value of a capacity of a corresponding wind turbine unit. The wind turbine units have the same reactive-power reference value, which is constant and does not change with time. The reactive power controllers of all wind turbine units have the same structure and parameters.

A power distribution arrangement for distributing AC power to loads requiring AC power is disclosed. The power distribution arrangement comprises a power distribution substation comprising transformers, switches, buses, and feeders, a DC transmission line, and at least one control unit. The control unit may control operation of the switches to selectively connect or disconnect one or more feeders to or from at least one transformer via one or more buses and to selectively connect or disconnect the DC transmission line to or from one or more feeders via at least one bus, whereby AC power is distributed to the loads via the feeders. The control unit may control operation of the switches based on: loading in and a power transfer rating of respective feeders and transformers, and any power transfer via the DC transmission line from the other power distribution substation to the at least one bus.