The invention relates to a grounding fault protection method for a high-voltage capacitor of a direct-current filter. The method comprises the following steps of acquiring a head end voltage u and an unbalanced current i.sub.T2 of a direct-current filter, and acquiring a discrete head end voltage and unbalanced current sequence; calculating a virtual capacitance C.sub.zd; determining a protection setting value C.sub.set according to the bridge arm capacitance of the high-voltage capacitor, and when the virtual capacitance C.sub.zd is larger than the protection setting value C.sub.set, protecting and judging to be an internal fault; otherwise, protecting and judging to be an external fault.

It discloses a ring-connected bridge-type multi-port hybrid DC circuit breaker. When the number of ports is n, n is an integer greater than or equal to 2, the ring-connected bridge-type multi-port hybrid DC circuit breaker includes: an upper DC bus bar, a lower DC bus bar, n thyristor arms, n diode arms, a main breaker branch, and n bypass branches; each thyristor arm connects in series with a diode arm, forming a series circuit; a bypass branch is connected between every two adjacent series circuits, a port is provided at the connection point of the thyristor arm and the diode arm in each series circuit, and the port is used to connect the protected components or the DC lines.

A bipole power transmission scheme typically includes a first converter station that is positioned remote from a second converter station, along with first and second transmission conduits which interconnect the first and second converter stations to permit the transmission of power between the first and second converter stations. The first converter station has first and second power converters, with the first power converter including a first DC terminal that is connected with the first transmission conduit, at least one AC terminal which is connected with a first AC network, and a second DC terminal that is interconnected with a third DC terminal of the second power converter by a first interconnection which defines a first neutral area. The second power converter additionally includes a fourth DC terminal that is connected with the second transmission conduit and at least one AC terminal which is connected with a second AC network.

This application discloses a system that may comprise at least a portion of a supply network. The system may further comprise a load controller that controls current flow with a current level of I1 into a load network that provides power to one or more loads from the at least a portion of the supply network according to a preprogrammed load curve. The system may also comprise a protection system that isolates the at least a portion of the supply network from the load controller in response to detecting a current pattern that is inconsistent with the preprogrammed load curve.

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 pertains to devices, systems, and methods for monitoring a direct current (DC) system. In one specific embodiment, a system may include a centralized protection and control (CPC) system. The CPC system may include a DC interface configured to be in electrical communication with a first DC system and a communication subsystem configured to receive a first measurement, from a remote device, of at least one electrical parameter of the first DC system. The CPC system may also include a DC monitor subsystem to generate a second measurement of at least one electrical parameter of the first DC system based on the electrical communication between the DC interface and the first DC system and generate a comparison of the first measurement and the second measurement. An action subsystem may generate an action based on the comparison between the first measurement and the second measurement.

An electronic valve apparatus for a high voltage direct current, HVDC, power transmission system. The electronic valve apparatus includes a first device chain including a number of first devices connected in series between an input node and an output node. Each of the first devices has an asymmetric transfer function configured substantially to block current flow through the device in a first direction, and the first devices are connected such that they all block current flow in the same direction. The electronic valve apparatus also includes a second device chain including a number of second devices connected in series between the input node and the output node. Each of the second devices has an asymmetric transfer function configured substantially to block current flow through the device in a first direction, and the second devices are connected such that they all block current flow in the same direction.

A power converter between an AC side and DC of the power converter is disclosed. The AC side is connected to an AC supply grid and the DC side is connected to a DC grid. The power converter includes a bridge circuit connected to the AC side of the power converter via AC switches and connected to the DC side of the power converter via circuit breakers, wherein a DC link circuit of the power converter is chargeable from the AC supply grid via an AC precharging circuit. The power converter has an insulation monitor to measure the insulation resistance of the DC side when the AC precharging circuit is connected to the DC link circuit. The disclosure also includes a related method.

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.

A electric aircraft power distribution system includes a first battery pack connected to at least a first load and to a common bus that connects the first battery pack in parallel to at least a second battery pack; a first electrical component electrically connected between the first battery pack and the first load and configured to disconnect the first load from the first battery pack in response to current above a first threshold current, wherein the first electrical component has a first disconnection time at the first threshold current; and a second electrical component electrically connected between the first battery pack and the common bus and configured to disconnect the first battery pack from the common bus in response to current above a second threshold current, wherein the second electrical component has a second disconnection time at the second threshold current that is higher than the first disconnection time.