Abstract: The current differential relay operates without adjustable settings, and includes a phase current differential element with a predetermined threshold, responsive to local phase current values and remote phase current values, to detect three-phase faults and producing a first output signal if the threshold value is exceeded. Either a negative sequence current differential element or two phase current differential elements, also having predetermined threshold values and responsive to the local and remote phase currents, detect phase-to-phase faults and phase-to-phase-to-ground faults and produces a second output signal if the predetermined threshold is exceeded. A negative sequence or zero sequence current differential current element, with a predetermined threshold value is responsive to the local and remote phase currents to detect phase-to-ground faults and to produce a third output signal if the threshold is exceeded.

Abstract: A method and apparatus for monitoring a centrally controlled power distribution system is provided. The method includes sampling an electrical current flow in the centrally controlled power distribution system, transmitting the sampled current signals to a central control processing unit, determining a ground fault presence and location based on the current signals received from all of the node electronics units, and isolating the determined ground fault by opening circuit breakers supplying power to the fault. The apparatus is configured to sample an electrical current flow in the centrally controlled power distribution system, transmit the sampled current signals associated with each circuit breaker to a central control processing unit, determine a ground fault presence and location based on the current signals received from all of the node electronics units in the power distribution system, and isolate the determined ground fault by opening circuit breakers supplying power to the fault.

Abstract: Devices and methods for detecting islanding operation of a static power source involve injection of a non-harmonic error on the phase angle of the static power source in regular steps to introduce a very small intentional phase shift for the output voltage of the static power source in every voltage cycle which is corrected in each cycle in synchronization with the grid voltage in normal operation of the grid. In abnormal operation of a grid loss, this intentional small phase shift or error causes an intentional small frequency drift in each voltage cycle that continues in one cycle after another cycle. When the intentional frequency drift is over a preset level, a detection circuit starts to isolate the static power source from the grid to prevent islanding operation.

Abstract: An electric plant with a safety device, a method for remedying faults in a switchgear installation, and the use of a closing contact to provide security against faults. The plant includes a switchgear installation, consumer loads connected to the switchgear installation, and at least one feeder cable to the switchgear installation. The plant provides a strong consumer network that still has a high degree of safety against damage caused by short-circuiting faults. The plant includes at least two feeder cables, each connected to its own current source such as a transformer or a generator. At least one of the feeder cables is connected by a branch cable to ground. The branch cable is provided with a closing contact, which is normally open. The closing contact is arranged to be activated, i.e. to quickly close the connection to ground, in the event of short-circuiting in the switchgear installation.

Abstract: A method of and a device for operating a decentralized control system, at least two control units are provided to control at least one actuating element each. In this control, different operating modes are to be differentiated, the selection of the respective operating mode of the individual control unit is made by the at least two control units on the basis of at least one status signal.

Abstract: A method and a device for protecting at least one consumer against overvoltages when working with a method for non-contact transmission of electric power from one or more medium-frequency current sources, whose frequencies may have deviations around medium frequency fM, to the at least one moving consumer via one or more transmission lines and transformer heads, allocated to the consumers, having a downstream matching controller for adjusting the power received from the transmission line; a transmission line is fed from a medium-frequency current source with a medium-frequency current that is constant in its effective value during the power transmission; the respective consumer is supplied with energy by at least one matching controller having at least one feed-in; one or more fed currents are rectified in each instance in a rectifier, smoothed in each instance by a link-circuit reactor and brought together; with the aid of a switch, the link-circuit current, brought together in each instance, is either suppl

Abstract: A High Speed Transfer System which comprises three Protection and Control devices. A first and a second of said Protection and Control devices are used for failure detection on the feeder bus-bar; the third of said Protection and Control devices is used for the High Speed Transfer System co-ordination functionalities.

Abstract: In one embodiment, an integrated differential isolation loss detector is disclosed that generates a first temperature that is a function of a high side current and a second temperature that is a function of a low side current. A temperature sensor senses the difference between the first and second temperatures and provides an output signal that is indicative of the magnitude and the polarity of the sensed difference. A controller receives the output signal and if the difference is greater than a predetermined magnitude the high side current, the low side current, or both can be disconnected from the load. In another embodiment, an integrated differential isolation loss detector is disclosed that includes a first temperature difference generator that generates first and second temperatures where the difference between the first and second temperatures is a function of the magnitude of the high side current.

Abstract: The substation control system, being responsive to a plurality of status input signals from various power system assemblies includes a plurality of input/output modules, each having a fiber-optic transceiver capability, wherein wire connections are used to communicate the status signals from the power system assemblies to input contacts of the respective I/O modules. The output signals from the I/O module are applied to a fiber-optic line. The system also includes a plurality of logic processors, each responsive to the signals on a fiber-optic line from a plurality of input-output modules for application to a plurality of protective relay devices, which provide protection operations and generate output signals. The logic processors also have a part in the overall protection arrangement. The output signals are communicated back to the power system assemblies for local control and protection thereof and to SCADA systems for remote control thereof.

Abstract: An apparatus for anti-islanding protection of a distributed generation with respect to a feeder connected to an electrical grid is disclosed. The apparatus includes a sensor adapted to generate a voltage signal representative of an output voltage and/or a current signal representative of an output current at the distributed generation, and a controller responsive to the signals from the sensor. The controller is productive of a control signal directed to the distributed generation to drive an operating characteristic of the distributed generation out of a nominal range in response to the electrical grid being disconnected from the feeder.

Abstract: An electrical load drive control apparatus includes: a plurality of drive units, each of which drives one of a plurality of electrical loads; an instruction unit that issues a drive switch instruction to switch drive among the plurality of electrical loads; a detection unit that detects a non-operating state of the plurality of electrical loads; and a control unit that controls the plurality of drive units based upon the drive switch instruction issued by the instruction unit and results of a detection by the detection unit.

Abstract: A generator for producing high voltages and having at least one generator winding (12) is connected via a generator circuit (10) to a network (19), which generator circuit has means (15, . . . , 17) for protection against overvoltages. Improved protection against higher voltages is achieved in that the at least one generator winding (12) is subdivided into a number of winding sections (12a-c) whose winding insulation is designed such that the insulation level is graduated, and in that the overvoltage protection means have a number of overvoltage protection elements (15, . . . , 17), which are associated with the respective individual winding sections (12a-c) and whose response levels are matched to the requirements of the associated winding section.

Abstract: An automatic transfer switch and protection device is provided. The device includes a contact, a drive assembly, and a controller. The contact is movable among a first position, a second position, and a third position. The drive assembly moves the contact among the first, second, and third positions. The controller receives a first signal indicative of a condition of power in a first power source and a second power source. The controller provides a second signal to the drive assembly to move the contact in response to the first signal. The contact can provide power to a load from the first source in the first position, from the second source in the second position, and can isolate the load from the first and second sources in the third position.

Abstract: A control arrangement and method is provided for detecting and responding to disturbances in electrical power systems. In a preferred arrangement, an integration is initiated that is based on a comparison of actual voltage of a source and a reference voltage. When the integration exceeds a predetermined value, the source is considered unreliable. Also in a preferred arrangement, a determination is made as to whether or not the disturbance is a downstream fault condition. For example, this is useful for applications where a transfer is made from a first source to a second source when predetermined disturbances are detected. In this manner, the transfer of the load to a second source is avoided which would continue the supply of the downstream fault. Additionally, the arrangement distinguishes between various degrees of disturbances to permit appropriate response based on the severity and type of disturbance. For example, a first immediate response, i.e.

Abstract: Protection systems for electrical systems such as substation power dividers are described. The protection systems may be designed and used to detect and clear faults that may occur within the substation power dividers. For example, a first Rogowski coil may be used to detect current along a primary conductor, and output a corresponding current signal to a multi-function, differential relay having multiple voltage and current inputs. Similarly, additional Rogowski coils may be used at each of a plurality of secondary feeders, where power from the primary feeder may be distributed to the secondary feeders using a connection bus. By comparing the signals from the first Rogowski coil and the additional Rogowski coils, the differential relay may determine whether a fault exists at some point along the conductor(s) and between the first Rogowski coils and the additional Rogowski coils, including whether a fault is associated with the connection bus.

Abstract: In order to receive protection commands in a remote tripping device, one or more signals is or are received, protection commands and combinations of protection commands are coded by means of an individual signal or by means of a predetermined combination of signals, and each protection command is allocated a predetermined minimum safety and/or security value.

Abstract: A SkyCharger™ Node or “Node” that contains programmed instructions and/or “intelligence” for monitoring communication traffic on a communications network such that appropriate reactions to commands received over the communications network occurs. The “Nodes” also broadcast commands and status information to the network for the purpose of being monitored and/or responded to by other “Nodes” on the network. The “Nodes” provide a way to monitor, control, provide information to or from, or react to, information provided by way of SkyCharger™ network(s).

Abstract: A ground relay system is provided which includes: first current transformers located in the respective phases of a sending end of a high-voltage distribution provided from a distribution substation; over-current relays connected to the first transformers; distribution transformers located in the respective phases in the respective sections of the distribution; second current transformers connected to secondary sides of the distribution transformers; current converters connected to the second transformers; and a current comparator that introduces the currents of the respective phases of the sending end of the distribution from the relays to produce a first zero-phase current, introduces the currents of the respective phases of a load end of the high-voltage distribution from the current converters to produce a second zero-phase current, and operates a ground protection relay that opens a circuit breaker inserted at the sending end of the high-voltage distribution if the level of the first current is larger.

Abstract: A method of protecting a section of a three phase power line uses superimposed current components in the power line to enable a local relay to detect operation of remote circuit breakers of remote relays in response to a fault on at least one phase of the power line. Line signal transducers output line condition signals indicative of voltage and/or current in the line near the circuit breaker, and a signal processor in the local relay processes the line condition signals to selectively produce a fault signal for opening its circuit breaker after taking account of remote circuit breaker operation.

Abstract: If an activation error occurs, after activation is executed for all devices, a device in which the activation error has occurred is reactivated. When the power supply of a television receiver is turned on, a control unit reads last conditions from a memory, and executes initialization according to the last conditions. When the television receiver is activated or the contents of settings are modified, if an activation error occurring in a tuner, a video processing unit, a sound output system, or any other device is detected, the activation error is recorded in a nonvolatile memory by setting a flag. A device recorded with the flag set is then restored (reactivated).

Abstract: Systems and methods for locating any grounded circuit on an ungrounded AC or DC system without de-energizing the circuit, and enabling isolation of the grounded component of the circuit. A load is fed through an isolation device, such as a transformer for AC systems or a DC-to-DC converter for DC systems, and isolated from the normal distribution system without ever being de-energized. Once the isolating device is paralleled with the normal source for the load, the normal source is removed, leaving the load energized and fed by the isolating device. A ground detector relay is added at the secondary side of the isolation device to detect unwanted grounds along with a ground locating method to isolate the source of the ground, such as by oscillating the ground current. Once the grounded circuit is located, further troubleshooting may be performed to isolate the grounded component.

Abstract: Certain exemplary embodiments provide a method comprising: detecting a NERC disturbance in an electrical power system; determining a first corrective action to return the electrical power system to a pre-disturbance level within a predetermined disturbance recovery time; determining a second corrective action to cause the electrical power system to meet one or more predefined NERC CPS compliance target values; and providing a corrective control signal to the electrical power system.

Abstract: The techniques described herein allow a wind turbine generator system to automatically capture voltage waveform data corresponding to a voltage disturbance event. Data corresponding to a period preceding the voltage disturbance event, during the event and a period of time after the event are captured and stored for further analysis. The sampling rate is relatively high compared to the frequency of the power provided by the generators.

Abstract: The invention concerns a local network for the transfer of information among several communication devices connected to an alternating current electrical power distribution system with a pre-determined frequency, the information conveyed in the local network being transferred in the form of electrical signals forming waves in the electrical power distribution system in a frequency band higher than the pre-determined frequency, the electrical power distribution system being connected to an electrical power supply system, characterized in that the local network comprises at least one wave reflection device forming reflected waves in the power distribution system and attenuating the waves of the power distribution network in the electrical power supply system. The invention also concerns the reflection device.

Abstract: A power supply method is provided in which a PPS can easily supply a commensurate amount of electric power from the one or more power generating units so as to be consumed by the one or more specific loads. According to one aspect of the present invention, a secondary battery is prepared; the difference between the amount of electric power generated by one or more power generating units and the power consumption of one or more specific loads is calculated; and depending on the calculated difference, electricity is supplied from the secondary battery to the one or more loads or a power transmission line network through an inverter, or the secondary battery is charged with electricity supplied from the one or more power generating units or the power transmission line network through a converter so as to solve such difference.

Abstract: An electric power supply system for a vehicle has an electric power line wired in a loop configuration. From the electric power line power is supplied to a load, and to another system which supplies control system power supply. One shutdown circuit is provided in a module connected to the loop configured power supply line. When the electric power line and the load are short circuited, the shutdown can isolate and shut down only the failure point. Further, when the car is not in use, by stopping the power supply to the load, current consumption can be restrained. In response to detection of a ground short and a failure of a connection of a connector, an over-current prevention of an electric power line, a simple construction can be provided and a low current consumption can be realized.

Abstract: In order to improve a line arrangement for electrical systems of vehicles, comprising an electrical supply line running from a current feed terminal to a current delivery terminal and having at least one current-carrying inner conductor and at least one protective sheath surrounding the latter in such a way that, when an arc forms, remedial action can be rapidly taken, it is proposed that a detector element which runs along the supply line and is formed in such a way that its electrical and/or optical behavior is irreversibly changed when a local arc originating from the current-carrying inner conductor occurs is provided, and that an isolating circuit which is connected to the current feed terminal and isolates the current-carrying inner conductor from a current source when the electrical and/or optical behavior of the detector element changes is provided.

Abstract: An interface apparatus for interfacing an AC power source, a control panel and a luminaire. The interface apparatus includes a input/output port that is adapted to receive a communication signal from the control panel and transmit the communication signal to the luminaire and to a second interface apparatus; and a power cord adapter, that is adapted to receive an AC power signal from the power source and provide the AC power signal to the luminaire and to the second interface apparatus. In another embodiment of the present invention, a luminaire provides an input/output port that is adapted to receive a communication signal from a control panel via the input port and transmit the communication signal to another luminaire via the output port.

Abstract: A distribution network monitoring and control system for monitoring and controlling a distribution network system including monitoring and control means for taking in an information and for outputting a control information for the switches thereof, status grasping means for judging charging and outage state of the distribution network system, switch status take-in means for taking in status of the switches in a range to which power was transmitted when the fault was generated, fault section judging means for judging a fault section according to a fault information, and fault section expanding means for expanding a fault section to a load side when status of the switches at the load side of the fault section cannot be taken out and for notifying an expanded fault section to the fault section judging means. The fault section judging means decides the expanded fault section as the fault section.

Abstract: In a relay unit, a communication signal is blocked and separated by a separator inserted to a power line. The communication signal provided from one end or another end of the separated power line through a switch is received by a receiver. The received communication signal is relayed by a processor, and the relayed communication signal is transmitted from a transmitter to the one end or the other end of the power line.

Abstract: A control system for canceling load unbalance of a three-phase circuit includes phase current detectors for detecting phase currents caused to flow through a secondary circuit of a current transformer provided in high voltage distribution lines, respectively, phase change-over switches through which phases of the high voltage distribution lines, and primary sides of distribution transformers provided across high and low voltage distribution lines are connected to each other, a control center for, when a magnitude of a zero-phase current detected by the zero-phase current detector is larger than a predetermined value, on the basis of the phase currents, respectively, out putting a control signal so that the load of the phase having a maximum current appearing therein is changed over to the phase having a minimum current recognized therein, and a phase change-over slave station for controlling the phase change-over for the phase change-over switches in accordance with the control signal.

Abstract: The current differential relay operates without adjustable settings, and includes a phase current differential element with a predetermined threshold, responsive to local phase current values and remote phase current values, to detect three-phase faults and producing a first output signal if the threshold value is exceeded. Either a negative sequence current differential element or two phase current differential elements, also having predetermined threshold values and responsive to the local and remote phase currents, detect phase-to-phase faults and phase-to-phase-to-ground faults and produces a second output signal if the predetermined threshold is exceeded. A negative sequence or zero sequence current differential current element, with a predetermined threshold value is responsive to the local and remote phase currents to detect phase-to-ground faults and to produce a third output signal if the threshold is exceeded.

Abstract: An electrical distribution board that stores terminals of a signal cable connected to a communication network and an electrical power cable connected to an electrical distribution cable, the electrical distribution board comprising: an in-building electrical distribution breaker inserted between the electrical power cable and the in-building distribution cable; a gateway that interfaces the communication network with the in-building network; and a plurality of optical repeaters, each having a bi-directional conversion function between an electrical signal and an optical signal between an electrical signal input/output terminal and an optical signal input/output terminal, and having an electrical signal input/output terminal that is connected to an electrical signal input/output terminal for in-building network connection of the gateway, wherein the optical signal input/output terminal is connected to an optical fiber cable of the in-building network.

Abstract: A harmonic wave distortion suppressor includes a main body, at least a connecting pin and a coating. The main body is made of a first material and covered with a second material for absorbing an instantaneous high voltage or sharp wave. The connecting pin is coupled to two lateral sides of the main body respectively so as to form a capacitor. The coating is coated on the main body locally with a clearance being exposed and the clearance provides a function of charging and discharging locally. When the high voltage or sharp wave passes through the harmonic wave distortion suppressor, peak discharging effect of the clearance can not only isolate the high voltage or sharp wave from entering an electronic device but also prevent an iron core in the electronic device from occurring magnetization effect resulting from the high voltage or sharp wave so that quality of signal transmission and receiving can be secured.

Abstract: A combined audio and power connector facilitates the use of portable audio devices with audio systems, including but not limited to vehicle audio systems. By integrating an audio input and a power supply into a single connector, the need to use multiple cords, e.g., one for the power supply and another for the audio input, is avoided. Further, a vehicle can deliver power to many types of portable devices without the use of relatively large auxiliary power jacks. As a result, many or most of the auxiliary power jacks currently incorporated in vehicle designs can be eliminated, making additional space available for other applications.

Abstract: An intelligent line switch and particularly a line switch equipped with an approaching or touching sensor, and an adjusting knob with a sensor of adjusting sensitivity. The line switch includes a switch operable in a manual mode or an automatic mode. The manual mode may control an electric device in a conventional way. When switched to the automatic mode, the sensor can detect approaching or touching of operator's hand. Thus operator can easily actuate operations of ON or OFF or adjustment of the electric device by merely a single motion such as approaching or touching with one hand without the complicated operations of approaching, grasping, depressing and leaving occurred to the conventional line switches.

Abstract: A recloser is monitored and adaptively controlled so that it will operate in a manner responsive to prevailing conditions as either a recloser or as a sectionalizer. The prevailing conditions that are determined are those that will affect the operation of the recloser, such as the number of faults, the fault current versus time, or the presence of reverse power.

Abstract: An electrical service distribution board is accommodated in a housing, has a feed conductor that is inserted into the housing and has outgoer conductors that lead to individual loads. Electrical service devices with different protection tasks, such as fault current protection, short circuit or over-current protection and the like, which can be connected to the feed conductor and to the outgoer conductors by a plug connection via a connection system which contains connection conductors connected to them. A mounting plate is providing for holding the service devices, with the connection conductors disposed underneath the mounting plate and the mounting plate having openings into which plug elements which are disposed on the service devices can be inserted.

Abstract: An object of the invention is to provide an electrical contact of a low surge type which is easily manufactured, has a small environmental influence, and has a small chopping current value, a manufacturing method of the same, a vacuum interrupter using the same, and a vacuum circuit-breaker using the same. The invention provides an electrical contact having a high conductive metal, and a refractory element constituted by a metal nitrogen or a metal oxide. The high conductive metal can employ Ag or Cu or alloys mainly containing either Ag or Cu, the metal nitride can employ one or mixture of two or more of Mg3N2, AlN, TiN, ZrN, CrN, Cr2N, NbN, BN and Si3N4, and the metal oxide can employ one or mixture of two or more of MgO, Al2O3, TiO2, Ti2O3, ZrO2, ThO2, Cr2O3, Nb2O5, Y2O3 and ZnO. Accordingly, it is possible to secure an improved resistance welding performance.

Abstract: A circuit protection system is provided that provides dynamic zones of protection for the circuit. The zones of protection can be based in part upon the topology of the circuit. The protection system can perform various dynamic zone protective functions for the zones of protection.

Abstract: The invention relates to an electrical installation, especially a medium-voltage switchgear, comprising at least one encapsulated function module (FM), a decompression channel (DK) which is connected to said function module, and at least one inflow opening (EO . . . ) which connects the function module (FM) to the decompression channel (DK). The covering surface (DF 1,2,3) of the decompression channel (DK), opposite the inflow opening (EO . . . ), comprises at least one partial region which is obliquely oriented in relation to the inflow direction. Hot gases and high pressures produced during an accidental are can thus be evacuated from the installation, without any risk to humans and buildings. Pressure channels are used, inter alia, in installations used in relation to medium-voltage technique for providing and distributing energy.

Abstract: Protection is provided for servicing a distribution bus by grounding the line side of a circuit breaker through which the distribution bus is fed and then closing the circuit breaker. The trip unit of the circuit breaker includes logic, in addition to the normal protection logic, which opens the circuit breaker main contacts without delay if current is detected upon closing of the grounded circuit breaker. However, if the grounded circuit breaker has been closed for a selected period of time and then current is detected, the distribution bus is kept at zero potential by not operating the breaker. A breaker auxiliary switch with a mechanical delay provides the indication of the selected time interval after closing the circuit breaker.

Abstract: A central office transceiver-installed current limiter and regulator provides fault isolation and transient load isolation in a wireline communication network, having multiple transceivers connected by respective span-powered wirelines to a common power source at the central office. Using a current-sense resistor and controlled switch in series with the wireline, the current-limiter and regulator processes input electrical power from the power source prior to coupling that power to a remote transceiver. To prevent overheating and substantial power dissipation in the current-limiting circuitry in the event of a prolonged fault condition, the controlled switch is alternately turned on and off.

Abstract: For the control of an electric power transmission network, where local protection functions are implemented by a plurality of local protection devices (3,3a,3b,3b′,3c) located at a plurality of locations throughout the network, the following steps are executed

Abstract: The invention relates to a drive control for an electric drive with a secure electrical separation of power element and control element. The aim of the invention is to reduce the number of components such as optic couplers and buffer amplifiers between the power element and a control electronics. To this end, a suitable electrical transformer (U) is inserted in a digital communication interface (K) between the control unit (R) and the control electronics (A) for the purpose of providing a secure electrical separation. To make use of a transformer (U) possible, a non-zero frequency encoding, for example a Manchester encoding, is carried out. Alternatively, an Ethernet physics can be used to provide a suitable communication interface. The transformer electrically insulates the two communication paths from each other that are provided in an Ethernet physics and preferably has little coupling capacity and a low attenuation factor.

Abstract: A multi-output electric power source device has at least two channels for producing a constant voltage and a constant voltage from a single input voltage. Each channel is provided with a switching regulator in the input stages thereof and a series regulator in the next stage thereof. An over-heat detector circuit is provided in common for both channels. When the over-heating of either one of switching transistors in the channels is detected, the switching regulators turn off both switching transistors thereby to interrupt both output voltages from being supplied to an external circuit. When an over-voltage is detected, series regulators also interrupt the output voltages from being supplied to the external unit.

Abstract: A power system bus total overcurrent system is used with a part of a power system which includes two buses and first and second power line portions which extend between them. A protective relay system includes protective relays for each of the first and second power line portions, located near the two buses, wherein the relays determine the total current into and out of each bus. The bus total overcurrent system includes first and second communication lines between each pair of relays and another communication line which extends between the first and second communication lines. In a current balance arrangement, the relays measure difference current using the same communication line arrangement between the two pairs of relays to determine a fault condition. Fault determinations are made in each case by the protection algorithms from total and difference currents.

Abstract: A shorting switch eliminates arcing faults in power distribution equipment. The shorting switch includes a magnetic core having a pin member and an opening. A conductor is electrically connected between the first and second terminals and passes through the opening of the magnetic core. A switch member is pivotally mounted to the pin member of the magnetic core and is adapted to pivot toward and engage the conductor in response to arcing fault current flowing through the conductor. A third terminal is electrically interconnected with the switch member. A latch member has a first position, which holds the switch member apart from the conductor, and a second position, which releases the switch member to permit the switch member to pivot toward the magnetic core and engage the conductor in response to the arcing fault current. A solenoid unlatches the latch member in response to an activation signal.

Abstract: A plurality of submarine cable transmission paths extending from a plurality of land-based terminal stations are connected with each other in a submarine branching apparatus, and an electric power feeding line is arranged between each land-based terminal station and an electric power feeding line switching unit of the submarine branching apparatus to supply electric power from the electric power feeding line to a communication signal of the corresponding submarine cable transmission path through repeaters. The electric power feeding lines are connected with each other in the electric power feeding line switching unit. A control signal superposed on the communication signal is sent to the electric power feeding line switching unit through one submarine cable transmission path, and the connection of the electric power feeding lines is switched according to the control signal.

Abstract: System and equipment protection is provided for an electrical power distribution system via one or more protection arrangements for detecting and responding to faults in electrical power distribution systems. The one or more protection arrangements detect whether faults are external or internal to a distribution equipment configuration in a power system via directional sensing. The protection arrangements also detect and respond to faults in a power distribution system utilizing various combinations of primary and back-up protection arrangements that are operational simultaneously and in both closed-loop and open-loop configurations.