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 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.

An underarm gang operated vacuum break switch (underarm switch) has an electrically live portion under a mounting arm, which provides advantages over the standard vacuum break switch, which have the electrically live portion above the mounting arm. Because the non-electrified mounting arm is above the electrified portion, the underarm switch is safer for perching birds and other wildlife. The nature of the underarm switch also provides other benefits including a disconnect blade that when opened creates a visual gap to ensure electrical discontinuity along with a safety locking arm tied to deactivating the underarm switch. Adding to the safety measures is a visual indicator that shows an electrician when the switch is live and safe to open the disconnect blade. Other safety measures include a shock absorber assembly and inertia slowing mass protecting electrical contacts within the vacuum break switch from failing.

The present disclosure relates to a method for protecting DC line impedance phase based on protection and control coordination, and an application scenario of the method for protecting is a three-terminal flexible DC transmission network. The method uses high controllability of a converter after a fault, injects a characteristic signal at a characteristic frequency, and calculates a phase angle of input impedance to determine a fault interval, which effectively improves protection performance, turns passive to active, and is not affected by nonlinearity of the converter. At the same time, compared with a full-bridge MMC, using a half-bridge MMC does not need to perform fault ride-through first when identifying a fault, and does not need to add additional equipment, it creates fault features and can reliably identify an fault interval; improves protection quickness and at the same time also has better economic benefits. It has selectivity, and an entire system may not be shut down due to failure of a single line.

This application discloses a photovoltaic direct-current breaking apparatus, including a positive connection terminal and a negative connection terminal for connecting a photovoltaic string and a photovoltaic energy converter, a first diode, a first switch, a convector circuit, and an energy absorption circuit, where the first switch, the convector circuit, and the energy absorption circuit are connected in parallel. The convector circuit can effectively avoid arc discharge and ablation generated when the first switch cuts off a direct-current circuit between the photovoltaic string and the photovoltaic energy converter. The first diode can effectively bypass energy stored by an energy storage device in the photovoltaic energy converter, helping reduce required specifications of a semiconductor device in the convector circuit. The energy absorption circuit can also effectively reduce required specifications of the semiconductor device and a varistor.

According to one aspect of the present disclosure, an energy storage system includes one or more power sources, one or more energy storage components, and one or more solid state circuit breakers disposed between the one or more power sources and the one or more energy storage components such that electrical power is exchanged between the one or more power sources to the one or more energy storage components through the one or more solid state circuit breakers. The energy storage system also includes a controller configured to operate the one or more solid state circuit breakers to control current exchanged with the one or more energy storage components and protect the one or more energy storage components from the one or more power sources during a fault condition.

An electronic fuse circuit for safeguarding a multi-channel electronic power distributor includes a driver circuit for each channel of the power distributor configured to control an electronic switch of a corresponding channel to assume a certain state, and a microcontroller interface configured to receive from a microcontroller a command for setting the state of the electronic switch of a corresponding channel. The driver circuit of the corresponding channel is configured to set the state of the electronic switch of the corresponding channel according to the command from the microcontroller. The electronic fuse circuit further includes a safety circuit for detecting a malfunction in the microcontroller and/or the power distributor. In the event of a detected malfunction in the microcontroller and/or the power distributor, the driver circuit of each channel is configured to set the state of the electronic switch of the corresponding channel according to a channel-specific preconfigured safety state.

In a power supply system, a first route includes a first power supply connected to a first load. A second route includes a second power supply connected to a second load. A connection path connects the first and second routes at a connection point. The first power supply includes a voltage generator generating an operating voltage operating the first and second loads. The second power supply includes an electrical storage device charging based on power supplied from the voltage generator. A switching circuit includes a first switch having a diode component with an anode and a cathode being directed to the electrical storage device and the connection path, respectively, and is disposed between the connection point and the electrical storage device. A switch state controller outputs a switch-off command to the first switch when the electrical storage device is in the fully charged condition.

The invention discloses a commutation failure protection method, and apparatus, computer device and storage medium thereof. The method comprises: collecting three-phase AC currents on a valve-side of a converter, a DC current on a high-voltage side and a DC current on a neutral terminal; selecting a minimum value of an absolute value of the three-phase AC currents on the valve side as an AC characteristic quantity, and selecting a maximum value of the DC current on the high-voltage side and the DC current on the neutral terminal as a DC characteristic quantity; according to the AC characteristic quantity and the DC characteristic quantity, constructing a minimum characteristic quantity; comparing the minimum characteristic quantity with a first preset threshold, and outputting a commutation judgment result; according to the commutation judgment result, constructing a commutation time interval; comparing the commutation time interval with a second preset threshold and a third preset threshold, and outputting a commutation failure protection judgment result to determine whether a commutation failure occurs. The invention uses minimum current sequence characteristics to track a commutation process of a converter valve, and when a commutation failure occurs, it may make timely, accurate and reliable judgment, thereby ensuring safe operation of valve equipment.

Some embodiments provide a DC power distribution system that includes a plurality of DC sources coupled to a plurality of DC buses via respective protection devices that are configured to selectively cause an open-circuit between the DC source and the respective DC bus in the event of a fault or overload condition on the respective DC bus. The plurality of DC buses are coupled to a load combiner, and the system is configured to supply power in parallel from the DC sources via the plurality of DC buses to at least one DC/DC step-down converter via the load combiner, which combines the power supplied via the plurality of DC buses. The DC buses, load combiner, and the DC power sources are configured such that the total maximum load current is capable of being supplied via less than all of the plurality of DC buses in the event that any one of the DC buses is non-operational.