Abstract: An apparatus and a method are described for modifying test measurement signals for protective devices for electric power networks. The apparatus has an input interface to receive a first test measurement signal from a test generator, wherein the first test measurement signal is matched to a first electrical input characteristic of a first protective device for a power network. The apparatus further has an electrical modification system coupled to the input interface to convert the first test measurement signal into a second test measurement signal, wherein the second test measurement signal is matched to a second electrical input characteristic of a second protective device for the power network. The apparatus additionally has an output interface to output the second test measurement signal to the second protective device.

Abstract: A fail-safe motorized switching system includes: (a) a motorized loadbreak switch system, the motorized loadbreak switch system adapted for opening and closing contacts between a high voltage power source and a load; (b) an energy storage device connected to the motorized loadbreak switch system; and (c) a controller connected to the energy storage device, the controller programmed with control logic to ensure that the motorized loadbreak switch system opens the contacts between the high voltage power source and the load once the power source is removed.

Abstract: An apparatus includes a resistor assembly with resistors connected in series between a first terminal and a second terminal of a pilot conductor and/or a ground return of a ground monitor. The pilot conductor injects an electrical signal in a ground of a power cable assembly. A zener diode assembly is connected between a zener connection point and the ground return. The zener connection point is the first or second terminal. The zener diode assembly includes zener diodes connected in series between the zener connection point and the ground return and is sized to clamp a voltage from the zener connection point to the ground return to a value less than a zener threshold voltage. The zener threshold voltage is set above a nominal voltage on the pilot conductor. The components of the apparatus are spaced to prevent an arcing fault current for voltages less than 3000 V.

Abstract: The present disclosure provides a time synchronization method, including: acquiring, by a slave device, a first optical fiber transmission delay from a master device to the slave device, and a second optical fiber transmission delay from the slave device to the master device; exchanging a time synchronization signal with the master device, and calculating an initial time offset; adjusting the initial time offset by using the first optical fiber transmission delay and the second optical fiber transmission delay to obtain a corrected time offset; and adjusting a local clock according to the corrected time offset. Embodiments of the present disclosure further provide a corresponding device and system.

Abstract: Systems, methods, and devices relating to fault detection and short circuit current management support in power transmission and distribution networks using multiple inverter based power generation facilities. A fault detection process uses the waveshape (or the rate of change of the current) of the distributed generator output short circuit current to determine if a trip signal is required to disconnect the inverter based power generation facility from the transmission and distribution network. The process operates on DGs such as photovoltaic (PV) based solar farm. The present invention applies to the entire 24-hour period operation of inverter based DGs (e.g., solar farms, wind farms, fuel cell based DGs, etc.).

Abstract: A synchronization method for current differential protection comprises: selecting a point on the transmission line protected by the current differential protection; measuring the current and the voltage of each of the terminals of said transmission line; calculating the compensating voltage at the selected point respectively according to the measured current and the voltage of the each terminal; detecting and calculating the synchronization error by comparing all the compensating voltages.

Abstract: An arrangement for protecting equipment of an AC electrical power system comprises first means configured to measure the frequency of the current and voltage at at least one location in the electrical power system along an interconnection between two theoretical electric machines of an equivalent two machine system. Fourth means are configured to use the values of the frequency of the current and voltage measured to determine whether a power swing has occurred and if an occurrence of a power swing has been determined determine whether the measuring location is located on a motor side or a generator side of a potential pole slip electrical centre along said interconnection, the electrical centre being defined as the location where the voltage becomes zero during a pole slip, and send this information further to third means for use in a control for protecting equipment of the electrical power system.

Abstract: A line current differential protection system that uses an external time reference continues providing protection to a power apparatus upon the loss of the external time reference. An external time reference synchronization mode and a channel based synchronization mode may be selectively applied on a per channel basis such that only those channels in the system that are not guaranteed to stay symmetrical use external time reference synchronization.

Abstract: A semiconductor device includes: a first output unit configured to output a first phase; a second output unit configured to output a second phase different from the first phase, the second output unit being disposed to be stacked on the first output unit; and a controller configured to control the output units.

Abstract: A circuit breaker communication system is provided including a circuit breaker, an electronic module to record and store data associated with the operation of the circuit breaker, and a portable communication unit for downloading the stored data. The portable communication unit includes a power source, a display unit, a processor unit, a communication interface, and a keypad. Also, a cable is provided for interconnecting the portable communication unit to the electronic module. The cable is configured to carry a data signal between the portable communication unit and the electronic module, and to conduct power to the electronic module from the power source. The system may include an optical communication link to transmit to or receive signals from the circuit breaker, a transmitter to transmit data to the optical communication link; and a receiver to receive signals from the optical communication link.

Abstract: A system (10) is provided for communicating with a residential electronic circuit breaker (18, 20, 22, 24). The system (10) comprises a residential electrical wiring system (16) including a power line (28) and neutral line (32), a residential electronic circuit breaker (18) electrically connected to the residential electrical wiring system (16) and a programmer (34) configured to be selectively connected to the residential electrical wiring system (16) to communicate with the circuit breaker (18).

Abstract: An arc fault circuit interrupter includes separable contacts, a neutral conductor, an operating mechanism structured to open and close the separable contacts, at least one current sensor structured to sense current flowing through the separable contacts and output a sensed current value; and a processor. The processor includes a first routine structured to provide parallel arc fault detection, a second routine structured to provide series arc fault detection, and a third routine structured to enable the first routine and disable the second routine for a predetermined time when the sensed current value is greater than a predetermined value and to enable the second routine and disable the first routine for the predetermined time when the sensed current value is less than the predetermined value.

Abstract: The invention contemplates a technique for providing loop control on a faulted overhead or underground loop system, while preventing restored current from being fed or back fed into the fault. In particular, the invention provides a method, device, and system for restoring power to a faulted loop distribution system. The inventive method includes detecting a fault on the loop distribution system, interrupting current on the faulted part of the loop distribution system, isolating the faulted part of the loop distribution system from an unfaulted part of the loop distribution system, restoring current to the unfaulted part of the loop distribution system, and preventing the current from flowing to the faulted part of the loop distribution system. The method may further include providing the current to a load.

Abstract: A module is formed in which semiconductor components are soldered to an electrically conductive heat sink. The electrically conductive heat sink is formed so that it will serve as an electrical bus in an electronic device. The chips of the semiconductor component are metallurgically bonded to the surface of the heat sink. The heat sink uses a heat transfer fluid that flows through an interior of the heat sink, the interior containing an internal element. In the preferred embodiment, the internal element is a plurality of silver plated copper balls. The copper balls are brazed to each other and to the walls of the heat sinks in an assembly process. The heat sink housing will typically be made from copper, with one surface made from molybdenum so that the expansion and contraction of the heat sink housing molybdenum surface will be similar to that of the silicon substrate of the chips, thereby avoiding the problem of the chip substrate cracking and breaking due to thermal flexing.

Abstract: An oil-cooled inverter for an electric traction motor that uses six IGBT switches to generate 3-phase AC electrical current as its output. The switches are mounted on heat sinks that use hot motor oil (hydraulic fluid) as the heat transfer fluid. An interior of each of the heat sinks contains a heat transfer medium. The heat sink housing is made of molybdenum, which has a thermal expansion rate equal to that of silicon. This allows the circuitry of the inverter to be mounted directly on the top surface of the heat sinks, as the expansion and contraction of the heat sink housing will match that of the silicon substrate of the chips. Since both elements, the heat sink housing and the chip substrate, expand and contract at an equal rate during heating and cooling, the problem of the chip substrate cracking and breaking due to thermal flexing is eliminated.

Abstract: A protective relay, system, and relay operation method which allows logic functions to be distributed amongst multiple protective relays associated with a power distribution system. The protective relays include communications ports for exchanging messages over a peer-to-peer communications network, and include programmable logic. Each protective relay receives logic operands contained in the messages from remote protective relays, executes logic equations using the received operands, provides protective control if needed, and outputs operands to other protective relays.

Abstract: A fault protection apparatus is disclosed for use in a time graded fault protection scheme. The apparatus comprises a circuit breaker having a normally closed trip contact provided in a line, current measurement apparatus adapted to produce an output signal indicative to the current in the line at the circuit breaker, and fault signal processing apparatus adapted to process the output signal from the current measurement apparatus to detect an initial fault on the line at a first instance. The fault signal processing apparatus is further adapted to process the output of the current measurement apparatus after the initial fault has been detected and to produce an accelerated opening signal in the event that the output signal meets a predetermined criteria, and a control device which is adapted to open said circuit breaker trip contact in response to said accelerated opening signal.

Abstract: A protective relaying system includes a local protective relay operatively coupled to a protected line segment at a first location, and a remote protective relay operatively coupled to the protected line segment at a second location. The remote protective relay generates a signal (PILOT RECEIVE) to indicate the detection of a fault. This signal is communicated to the local protective relay and employed therein to supervise single-pole trip operations.

Abstract: An apparatus for enabling pilot wire relays to communicate across voice-grade, non-metallic communication channels converts sinusoid signals representative of phase currents at a location in an electric power distribution system to audio band signals representative of the phase of the current signal at that location. These audio band signals are transmitted over a voice-grade non-metallic communication channel to a remote interface module where they are converted to square waves which are compared against square waves representative of the currents in the electrical power distribution system at that location.

Abstract: Upon the occurrence of a fault on the first distribution line, a faulty section on the distribution line is pinpointed, then a tie point switchgear at the tie point between the first distribution line in which the fault occurred and the other normal second distribution line is closed to form a loop distribution system. Then, a switchgear adjacent to the fault point on the first distribution line is opened. An opposing switchgear adjacent to the fault point is opened on the condition that the fault occurrence continues after having been linked to the second distribution line. The above procedures are executed before the opening of the circuit breaker installed on the distribution bus bar.

Abstract: Active pilot wire apparatus for replacing a passive continuous metallic wire pair coupling between the electromechanical units of a conventional electromechanical pilot wire protective relay is disclosed. For the protection of a power line section, an electromechanical unit is coupled to each end thereof. Each electromechanical unit includes an operating relay coil which when energized operates breaker contacts to interrupt current through the protected power line section. A signal representative of the potential across the operating coil of each electromechanical unit is transmitted through an active communication channel to the other electromechanical unit where it is buffered by a high impedance amplifier. In each case, the output signal of the buffer amplifier is representative substantially of the corresponding operating relay coil potential. An impedance element is coupled between each buffer amplifier and the other operating relay coil.

Abstract: Direct transfer trip apparatus for sharing a common active communication channel utilized for signal transfer between at least two electromechanical units which form a current differential protective relay for protecting at least one power line in a power system network is disclosed. Each electromechanical unit includes an operating relay coil for effecting an interruption of current through the protected power line when an internal fault of the power line is detected. The direct transfer trip function induces signals to be transmitted through the common active communication channel either upstream or downstream from a faulted power line section where a breaker has failed to open. These direct transfer trip signals are supplied directly to an upstream or downstream breaker unit to operate the breaker to interrupt current through the faulted section independent of the energization of its corresponding operating relay coil.

Abstract: An echo-keyed directional comparison blocking system for protecting an electrical power transmission path in a power system network against internal faults is disclosed. The system includes a terminal unit disposed at each end of the transmission path for measuring characteristics representative of the power at its corresponding end and for activating a corresponding circuit breaker when an internal fault of the transmission path is detected. Each terminal unit includes a transmitter and a receiver for communicating transmit and receive signals with each other through a communication medium and additionally includes at least one forward-looking pilot relay, at least one over-current relay, and a plurality of circuits.

Abstract: Protective relaying apparatus of the pilot type, incorporating a direct transfer trip function (DTT) which reliably and securely utilizes the same communication channel utilized by the pilot relaying function. The DTT function operates within the constraints of a PPM modem, utilizing a signal extracted from the carrier signal, to provide a perfectly synchronized tone for the DTT signal.

Abstract: With heretofore known directional comparison protection systems working with fault direction detectors at both ends of a line section which is to be protected and data transmission between both end stations as well as transmitters and receivers and comparison-evaluation devices for narrowing or sectionalizing the location of the fault site with respect to the line section to be protected, the reliability of such sectionalizing procedure, especially in the case of faults near to an end station, when working with series capacitors or capacitance, is dependent upon the response of the protective gap of such capacitors. With non-response there are produced transient oscillations which can falsify the directional determination. The invention solves this problem by using distance protective relays as the fault direction detectors with line replica or image impedance, which can be switched in the sense of a zone staggering protection.

Abstract: A pilot wire relay protection system for detecting and responding to phase-to-phase, three-phase, phase-to-phase to ground, and ground current faults including relatively low level ground current faults occurring within an electrical power network is disclosed. The pilot wire relay protection system includes current transformers coupled to transmission lines of the electrical power network for developing coupled currents representative of the transmission-line currents. The current transformers are positioned at the ends of a section of the electrical power network for which protection is desired. The coupled currents from the current transformers are inputted to pilot relays having an analog device for producing a composite signal indicative of the condition of the protected section of the network. The pilot wire relay also includes an electronic device to detect if preset fault limits have been exceeded.

Abstract: In systems, such as aircraft electric power generation systems, three phase AC generators are often operated in parallel when supplying power to load busses and differential protection networks are utilized in each phase of each generator for detecting current imbalance between the phase conductor at the load and the neutral conductor of each phase. In this invention there is provided voltage limiter means such as back-to-back Zener diodes across each of the current transformers related to the phase and neutral conductors which, in conjunction with the other portions of the differential protection networks: (1) prevents nuisance tripping on the occurrence of high current faults outside the differential protection zone (such as bus faults) due to normal variations of the current transformers, and (2) at the same time, provides differential protection for a generator channel over the required range, generally from very low differential fault currents to the very high differential fault currents.

Abstract: A transfer trip circuit has a first station which contains a circuit breaker and a source of control current in which the control current is increased from a first value to a second value in response to the operation of the circuit breaker. A second station is connected to the first station by a pair of pilot wires which carry the control current. The second station contains a circuit breaker which is to be operated in response to the operation of the circuit breaker in the first station, and also contains two relay coils which carry the control current produced in the first station. The first relay coil operates an annunciator when the control current is below its first value to indicate a fault in the pilot wires. The second relay coil operates the trip circuit of the circuit breaker in the second station when the control current in said pilot wires is increased to said second value.