Abstract: Examples include a structure adapted for monitoring electric charge characteristics of the structure, where the wind turbine generator includes an electric charge monitoring system including one or more electrostatic sensors adapted for measuring polarity, the one or more electrostatic sensors being configured for measuring an electrostatic potential of one or more parts or at locations of the structure, where sensory data from the electrostatic sensors are time-stamped and time-synchronised, and the electric charge monitoring system is configured for monitoring charge characteristics at the one or more parts or locations of the structure.

Abstract: The present disclosure pertains to systems and methods for monitoring a capacitance-coupled voltage transformer (CCVT) in electrical communication with the electric power delivery system, the CCVT comprising a stack of capacitors and an electrical contact to a first ground connection. A first current transformer is disposed between the stack of capacitors and the first ground connection. The current transformer provides an electrical signal corresponding to a current associated with the CCVT. A second transformer is disposed to provide a second electrical signal related to the CCVT. The second signal may be a voltage signal or a current signal. An intelligent electronic device (IED) in electrical communication with the current measurement devices monitors a health factor comprising a ratio of magnitudes or a difference between phases from the transformers at a single frequency. The health factor is compared against an acceptable range and an alarm is generated when the range is exceeded.

Abstract: A connector system is provided for use in power applications, such as for conveying three phase power in electrical enclosures. The system comprises plug assemblies in which a power conductor is mounted in a floating arrangement with elastically deformable conductive structures extending from either side thereof. A mating receptacle may be mounted on a bus conductor. Three such arrangements may be provided for conveying three phase power. The structures allow for plug-in mating of the system components while accommodating considerable translational and angular misalignment between the connector parts.

Abstract: The present disclosure provides systems and methods for calculating the flux in a core of an unloaded power transformer using current measurements taken from a capacitance-coupled voltage transformer (CCVT) attached to the same phase line as the power transformer. According to various embodiments, the current sensors may both be positioned at zero-voltage points in the CCVT, eliminating the need for high-voltage insulated current sensors. An intelligent electronic device (IED) may determine the magnetic flux within the core of the power transformer using the measured and/or derived currents through capacitive assemblies of the CCVT. The IED may calculate the residual flux in the power transformer when it is de-energized. The IED may use the calculated residual flux to facilitate an optimized re-energization of the power transformer, thereby reducing inrush currents during re-energization.

Abstract: A power supply apparatus for a vehicle is provided which supplies electric power to a power supply unit and charges electric power from the power supply unit via a power port. The vehicle includes a plurality of power inverter circuits which are connected to a common storage unit in parallel. The plurality of power inverter circuits include an electric power transferring power inverter circuit connected to the power port via an electric power transferring electric path, and are divided into a first category including the electric power transferring power inverter circuit and a second category. The power supply apparatus includes a connection prohibiting unit which realizes a state in which the power inverter circuit included in the first category is electrically connected to the storage unit, and the power inverter circuit included in the second category is disconnected from the storage unit.

Abstract: A method is provided for manufacturing a wind turbine rotor blade in which the blade is formed as a laminated structure by laying a composite material of fibre reinforcement material and/or core material in a mould defining the shape of the blade; evacuating the mould after laying the composite material; introducing a liquid polymer into the evacuated mould and wetting the composite material; curing the liquid polymer after the composite material has been wetted; and removing the mould after curing the liquid. At least one lightning conductor is integrated into the composite material before wetting it with the liquid polymer. Moreover, a wind turbine rotor blade made from a single laminated structure is provided with at least one lightning conductor is integrated into the laminated structure.

Abstract: The invention relates to an overvoltage protection device, comprising at least one surge arrester and one switchgear assembly, which is connected in series to the surge arrester and which can be triggered thermally, wherein the aforementioned components form a structural unit, and the thermal tripping means is arranged in the area of the expected heating up of the surge arrester when overloaded. According to the invention, the thermal tripping unit is configured as a stop element through which operating current or surge current does not flow. In the event of thermal overload, the stop element opens a releasing device of the switchgear assembly, wherein said switchgear assembly has an increased self-extinguishing capacity.

Abstract: An arrester includes a switch and a lightning detection breaker connected to the switch. The lightning detection breaker includes a metal conducting terminal electrically connected to an earth return, a DC power supply terminal, a ground terminal and an output terminal. When the power supply is under a lightning strike, a potential difference of both the DC power supply terminal and the ground terminal of the lightning detection breaker will go up to several thousands of volts. However, a voltage of the metal conducting terminal will not go up because the metal conducting terminal is electrically connected to the earth return. The switch will automatically become open circuit by the lightning detection breaker, and therefore an electronic device connected to the arrester is protected from damage done by the lightning.

Abstract: In one embodiment, a wind-power generating system 10 includes: a lightning protecting device including a receptor 70 provided on a blade surface and a lightning conductor 73 grounding the receptor 70; an airflow generating device 60 provided on the blade surface and including first and second electrodes 61, 62 separated via a dielectric 63; a discharge power source 65 including switches 90, 91 able to connect the first and second electrodes 61, 62 to output terminals 84, 85 respectively and a switch 92 able to connect the first or second electrode 61, 62 to a grounding conductor 100; and a thundercloud detecting device detecting information regarding thundercloud approach. When the information regarding the thundercloud approach is detected, the second electrode 62 is connected to the grounding conductor 100 and the first and second electrodes 61, 62 are disconnected from the output terminals 84, 85.

Abstract: A fault sensor is disclosed for detecting the failure of a surge suppression device such as a metal oxide varister (MOV). The fault sensor comprises a fault sensor conductive layer overlaying an insulated portion of the surge suppression device. A fault sensor connector is connected to the fault sensor conductive layer for conducting a fault current upon a failure of the insulated portion of the surge suppression device.

Abstract: A method is provided for manufacturing a wind turbine rotor blade in which the blade is formed as a laminated structure by laying a composite material of fibre reinforcement material and/or core material in a mould defining the shape of the blade; evacuating the mould after laying the composite material; introducing a liquid polymer into the evacuated mould and wetting the composite material; curing the liquid polymer after the composite material has been wetted; and removing the mould after curing the liquid. At least one lightning conductor is integrated into the composite material before wetting it with the liquid polymer. Moreover, a wind turbine rotor blade made from a single laminated structure is provided with at least one lightning conductor is integrated into the laminated structure.

Abstract: A controller of a multi-phase electric motor has a drive section having an upper arm switching element and a lower arm switching element for driving the multi-phase electric motor, a single current detection section for detecting a current value of the multi-phase electric motor, a pulse width modulation signal generation section for generating plural pulse width modulation of each phase within one control period based on the current value detected by the current detection section and a carrier signal, and a phase movement section for moving the pulse width modulation signal of a predetermined phase generated by the pulse width modulation signal generation section by gradually changing a movement amount of the phase in one control period, and outputting the resultant pulse width modulation signal to the drive section.

Abstract: By means of a series of parameters taken by the plurality of sensors, the system of the invention makes it possible, via a central control unit provided with complementary programming firmware, to activate an electric-field compensating device (7) whenever there is a risk of lightning discharging over the wind turbine, in such a manner that, in the contrary case, said device remains inoperative. The electric-field compensating device (7) is associated not only with the nacelle (2) but also with the tower (1) and the blades (4) in such a manner that, between the rotor (3) and the nacelle unit (2) there is a first pair of rings (14), which are conducting, concentric and the dielectric of which is air, whilst, in the lower zone of the nacelle unit (2) there is a second pair of conducting rings (15) with similar features.

Abstract: A controller of a multi-phase electric motor includes a drive section for driving the multi-phase electric motor; a single current detection section for detecting a current value of the multi-phase electric motor; a PWM signal generation section for generating plural PWM signals of each phase within one control period based on the current value detected by the current detection section and a carrier signal; and a phase movement section for moving a phase by a predetermined amount such that frequency in change of the PWM signal of the predetermined phase generated by the PWM signal generation section is included in a non-audible range, and outputting the PWM signal which phase is moved to the drive section; wherein the phase movement section moves the phase by a predetermined amount for all the PWM signals of the predetermined phase within one control period.

Abstract: The invention provides a wind turbine with a lightning arrester system including one or more lightning receptors (R) mounted on one or more rotor blades. A down conductor electrically connects one or more lightning receptors (R) to electrical ground via a sliding contact arrangement (SC), and an electromagnetic radiation (EM) reduction device encircles a portion of the down conductor so as to reduce EM radiation from the down conductor due to static electric discharges caused by imperfect electric contact in the sliding contact arrangement (SC). Known types of EM radiation reduction devices in the form of commercially available common mode choke coils, cylindrically shaped nano-crystalline solid body types, or the like, can be used. A plurality of different types with different EM radiation reduction properties can be used in combination. To obtain more effective EM radiation reduction, a plurality of EM radiation reduction devices can be used, e.g.

Abstract: The invention relates to a transmission device for a wind turbine, having a holder, a sliding contact device having pressing means, and at least one electrode having adjustment means for transmitting lightning current. The electrode can form a spark gab having a sparking distance S together with a ring electrode, wherein the ring electrode can be arranged on the rotary device, or can be connected to a grounding device that cannot be rotated with respect to the rotary device. To improve the transmission, the holder is rotationally fixed arranged on the rotary device, or arranged in a non rotatable manner with respect to the grounding device. Furthermore, the electrode is arranged in a movable manner relative to the holder by means of a tracking device having support means. The electrode is supported by way of the supporting means relative to the rotary device or the ring electrode such that the sparking distance S can not fall below a minimum dimension.

Abstract: An electronic device includes a lightning protection circuit, a DC power unit, a housing, and a safety test switching device. The lightning protection circuit includes a circuit board, a fire wire, a ground wire, an AC power unit, and at least two protection elements. Both the fire wire and the ground wire are coupled to the DC power unit and the AC power unit. The housing includes a bottom board. The circuit board is disposed on the bottom board. The safety test switching device includes a conduction block formed on the circuit board and a conductive plug. The conduction block defines a threaded hole. The conductive plug is detachably plugged into the conductive block, when the conductive plug is detached from the conductive block, the lightning protection circuit and the ground are an open circuit.

Abstract: A reverse-connection protecting device comprises an interface, a battery control module and an activation module. The interface includes first and second lead-in ends coupled to respective ones of first and second lead-out ends. The second lead-in end is couplable to a negative terminal of a backup battery. The second lead-out end is couplable to each negative terminal of a load and an external power supply. The battery control module is coupled to the first lead-in end of the interface and couplable to a positive terminal of the backup battery. The battery control module is configured to control the charging or discharging of the backup battery. The activation module is coupled to the battery control module, and couplable to the load and the external power supply.

Abstract: A method of eliminating arc flash in a motor control center is disclosed. The method includes sensing an arc flash corresponding to the motor control center. In response to sensing the arc flash, and subsequent to a delay, determining whether the arc flash continues, and in response to determining that the arc flash continues, triggering an arc crowbar.

Abstract: A smoke/heat detector and alarm system for shutting off power to a heat generating appliance (gas or electric powered) when smoke/heat is detected. The system includes a smoke/heat detector that responds according to a selected one of four selectable modes. The system also includes a library of telephone numbers with corresponding emergency telephone numbers that are automatically dialed in response to reception of a Smoke alarm signal. The system is designed to avoid confusion that might otherwise be encountered when a plurality of such systems are operating in close proximity to one another.

Abstract: A structure for installing a lightning arrester between the cross arm mounted to the upper end of an electric pole and a power line is disclosed. A dead end clamp, the lightning arrester and an insulation reinforcing insulator are connected in series, an end of the insulation reinforcing insulator is connected to the cross arm by a shackle, a disconnector is connected to the voltage outlet portion of the lightning arrester, a grounding wire for diverting abnormal voltage to the ground is connected to the disconnector, and an insulation cover surrounds the dead end clamp and the voltage inlet portion of the lightning arrester.

Abstract: A housing encapsulating first and second terminals of a surge arrester disconnector becomes structurally weakened before activation of a disconnect device in the disconnector when the disconnector is exposed to heat, thereby preventing the disconnector from producing a projectile with a force sufficient to classify the disconnector as a hazardous material under Department of Transportation regulations.

Abstract: A protection device for protecting an electrical installation, which protection device is designed to be connected in parallel with the electrical installation and includes at least two electrically conductive contact members (3, 4) that are suitable for going from a closed position to an open position when a current (I) of magnitude greater than a predetermined threshold value passes through the protection device (1), said protection device being characterized in that, in the closed position, the contact members are separated from each other by a potentially insulating piece (15), thereby forming a spark gap (E) for protecting from voltage surges between the contact members (3, 4). The invention also relates to apparatus for protecting electrical installations.

Abstract: The voltage surge protection device comprises at least one protection module designed to be connected to an electric switchgear apparatus. The protection module comprises at least one protective element for protection against voltage surges and separating means connected to at least one protective element to cause an electrical and/or mechanical separation representative of a fault of a protective element following an increase of temperature and/or electric current. The protection module comprises means for mechanical actuation connected to said separating means and comprising a mechanical control link. The electrical control link is placed in a tripped state representative of a fault of at least one protective element when said separating means have caused a separation.

Abstract: The invention relates to an automatically quenching surge arrester arrangement with a surge arrester, which, on exceeding a given first voltage, transforms from a non-conducting into a conducting state and returns to the non-conducting state only when a much smaller second voltage is dropped below and with a switch mechanism reacting to current flow through the surge arrester, interrupting the current flow through the surge arrester and then automatically returning to the rest condition thereof. A simple, robust and compact assembly suitable for HF applications for such a surge arrester arrangement is achieved, whereby the switch mechanism reacts reversibly to the heat generated in the surge arrester by the current flow.

Abstract: A protector for an electric device comprises a driving device and a voltage stabilizing device serially connected to the voltage stabilizing device. After a switch of a power source is turned on, a current of high voltage flows into the voltage stabilizing device. Two conductive plates inside the voltage stabilizing device are electrically conducted and a current flows into the driving device. A spring plate having a semiconductor chip is then separated from an other spring plate and then returns back to contact together with the other spring plate. Meanwhile, the extra current of the power source is consumed such that the surge current instantly generated from power source is consumed, and damage to the electric device is prevented.

Abstract: A current pause device configured to enhance the operation of transmission and distribution line circuit interrupters by delaying the voltage build across the circuit interrupter arc gap for a time period sufficient to allow the dielectric characteristic of the medium within the arc to recover. This allows the circuit interrupter to break the circuit at a lower arc gap voltage than would occur without the current pause device. The current pause device includes a conductive arcing horn and an insulator interposed in the arcing horn to create a conductive gap in the arcing horn and a voltage protection arrangement to limit the voltage across the current pause device and thereby prevent a voltage breakdown across the current pause device. Specifically, the voltage protection arrangement includes a diode connected to the arcing horn in parallel with the insulator and a dielectric spark gap device connected in parallel across the insulator.

Abstract: The switchable lightning-arrester system has a safety-switchable connector (10), which, for differing power-line features, can include optionally a counter-lever safety connector (14), a slide safety connector (40), a hinged safety connector (56) and a pivot safety connector (67) intermediate a power line (11) and a lightning arrester (1) for on-spot disconnection to protect workers from self-destructing arresters when changing lightning arresters or working on damaged lines without costly, time-consuming and power-disruptive shutdown of power lines. This is highly important because the lightning arresters are changed and repair work is done on damaged lines as quickly after self-destruction from lightning surges as possible requiring the change and repair. The safety-switchable connectors are made to be operable and changeable from a safe distance remotely, which is preferably from a ground position near a light pole, a transformer or other line support (9).

Abstract: An isolating circuit breaker (40) for pole mounting (12) in relation to a electrical distribution line, said isolating circuit breaker including: an isolating switch (50) with a pivoting link (52), said isolating switch having respective terminals (45, 44) for electrical coupling to load and supply conductors (54, 53) of the electrical distribution line; a circuit interrupter (55) disposed in series with the isolating switch (50), intermediate said load and supply conductors and preferably incorporated in the pivoting link of the isolating switch; an actuator (58) arranged for selectively opening and closing the circuit interrupter (55); an electronic controller (61) controlling operation of the isolating circuit breaker in response to electrical conditions in the distribution line; and said isolating switch, circuit interrupter, actuator and electronic controller arranged together on a mounting structure (41, 42, 43) adapted for pole mounting.

Abstract: An isolating circuit breaker (40) for pole mounting (12) in relation to a electrical distribution line, said isolating circuit breaker including: an isolating switch (50) with a pivoting link (52), said isolating switch having respective terminals (45, 44) for electrical coupling to load and supply conductors (54, 53) of the electrical distribution line; a circuit interrupter (55) disposed in series with the isolating switch (50), intermediate said load and supply conductors and preferably incorporated in the pivoting link of the isolating switch; an actuator (58) arranged for selectively opening and closing the circuit interrupter (55); an electronic controller (61) controlling operation of the isolating circuit breaker in response to electrical conditions in the distribution line; and said isolating switch, circuit interrupter, actuator and electronic controller arranged together on a mounting structure (41, 42, 43) adapted for pole mounting.

Abstract: A surge arrester includes an electrically insulating arrester housing and a surge arresting block housed within the electrically insulating arrester housing. The surge arresting block is arranged to provide support for the surge arrester without the use of a support member. The surge arresting block may be a single surge arresting block having a voltage rating of at least 9 KV. The surge arresting block may have threads formed integrally therewith.

Abstract: A surge arrester includes a mounting bracket, a surge arresting element, an electrically conductive connector, and a fault disconnector. The mounting bracket forms a bracket cup. The surge arresting element is arranged to conduct in the presence of a surge. The electrically conductive connector is electrically coupled to the surge arresting element and forms a connector cup. The electrically conductive connector is received by the mounting bracket so that the bracket cup is received in the connector cup. The fault disconnector is arranged to disconnect the surge arresting element from an electrical line in the event of a fault, and the fault disconnector is housed within the housing formed by the connector cup and the bracket cup.

Abstract: A spark gap assembly includes two conductive spark gap points forming a spark gap. Two substantially identical, non-conductive, molded plastic pieces are clamped together to make a housing with at least one cylindrical receptacle for the spark gap points. Two conductive leads electrically contact the spark gap points and abut and electrically contact circuit board leads when the assembly is mounted on a circuit board. The housing pieces include at least one fastening hole and a fastener extends through the fastening holes when the pieces are assembled, thus clamping the together. The two pieces have at projections on the bottom that are received in holes on the board, thereby positioning the pieces.

Abstract: An electrical component is installed in a plastic cup. The component has two electrical connecting lines, and a parting location that is bridged by a solder metal is arranged in one lead. In addition, a prestressed spring is arranged at the one lead for removing the lead from the parting location during melting of the solder metal as a result of an overload, so that the component is disconnected from a current source. The one lead is pinched to a thickness of 0.2-0.5 mm.

Abstract: A method for determining the extent of a transient's ability to cause MOV over heating and subsequent explosion by microprocessor analysis of an AC voltage input waveform with respect to a stored perfect sine wave. The microprocessor also calculates the RMS value of the applied voltage waveform and compares it to stored limits to determine if it could cause over heating of the MOV. In either case, the microprocessor will generate an out-of-range signal to a disconnect device to take the MOV, and also the load, if desired, off line until normal line voltage is restored.

Abstract: The lightning arrester assembly for an overhead line for transporting electricity comprises a lightning arrester connected in series with a horned spark-gap between the electricity transport line and a support structure in the form of an arm of a pylon connected to ground. The assembly also includes a device for flagging a malfunction of the lightning arrester, which device is connected in series with the lightning arrester on one of the horns of the spark-gap.

Abstract: A surge protector module is provided with a housing with an internal space, a separator disposed within the housing which divides the internal space into first and second spaces within the housing, and a surge protection device. The surge protection device has a surge protector mounted within the first space and a disconnect mechanism operable to conductively disconnect one of the terminals of the surge protector from one of the terminals of the surge protection device in the presence of a prolonged overvoltage surge across the terminals of the surge protector. A combustion-retardant material is disposed within the housing of the surge protector module so that it occupies only the first space within the housing, leaving the second space within the housing substantially free of the combustion-retardant material, and the disconnect mechanism is disposed in the second space in which no combustion-retardant material is disposed.

Abstract: A surge arrester includes an electrically insulating arrester housing and a surge arresting block housed within the electrically insulating arrester housing. The surge arresting block is arranged to provide support for the surge arrester without the use of a support member. The surge arresting block may be a single surge arresting block having a voltage rating of at least 9 KV. The surge arresting block may have threads formed integrally therewith.

Abstract: An apparatus includes a surge arresting element, first and second end caps, an arrester housing, and a fault disconnector. The surge arresting element is arranged to conduct in the presence of a surge on a power line. The first and second end caps are arranged to be electrically connected to the surge arresting element, and the second end cap forms a disconnector housing. The arrester housing is arranged to house the surge arresting element and the first and second end caps so that the disconnector housing is accessible from an exterior of the arrester housing. The fault disconnector is arranged to electrically disconnect the surge arresting element from the power line in the event of a fault, and the fault disconnector is housed within the disconnector housing formed by the second end cap.

Abstract: A lightning arrester device with a housing (7) having two electrical contact terminals and consisting of at least one housing element (7a, 7b) containing at least one protective element (13) with terminals electrically connected to the contact terminals, the protective element being embedded in an insulating material (17) contained in the housing element (7). At least one sturdy sleeve (19) is inserted between the housing element (7) and the protective element (13) in the insulating material (17). The housing element (7a, 7b) constitutes one of the contact terminals.

Abstract: The invention relates to a surge arrester arrangement comprising a surge arrester with a number of ZnO blocks arranged between two end electrodes as well as a cut-out device arranged in series with the arrester for automatically disconnecting the arrester in the event of arrester failure. The central part in the cut-out device is a ZnO block (1) with a higher relative energy capability than the blocks in the arrester. In this way, the block in the cut-out device can only break if the arrester connected in series with the device has failed, whereby incorrect tripping of the device is prevented.

Abstract: A power apparatus in which a particle in an enclosure of the apparatus containing an electric conductor therein is moved in the enclosure by an electric field so as to cause an abnormality of insulation. The apparatus includes a first sensor for detecting an existence position of the particle on the basis of a sound of collision of the particle against the enclosure, a second sensor for detecting a partial discharge generated in the enclosure, and a device for receiving respective detection signals from the first and second sensors, for judging the existence of insulation abnormality caused by the particle inside the enclosure, and for outputting a result of the judgment.

Abstract: An arrester for an under oil transformer is connected between a primary bushing lead and an insulator/isolator penetrating the wall of a housing which encloses the oil, arrester, and transformer parts. A ground wire outside the housing is removably connected to the isolator which functions as a circuit disconnector. The ground wire is removed to open circuit the arrester so that the transformer may be tested without having to disable any parts in the housing. Responsive to an arrester failure, the ground wire is blown away to give a visual indication of the failure. The blowing away of the ground wire eliminates the need for the arrester to fail in an open circuit condition.

Abstract: In a switch gear, such as a high-voltage enclosed switchboard and a vacuum load-break switch, of the type wherein items of electrical equipment including disconnecting devices and circuit-breaking devices are installed within a case, masses of a silicone gel are filled in compartments accommodating the electrical equipment instead of the sulfur hexafluoride used heretofore. An air space is left above the silicone gel in each compartment. This construction enables the provision of a safer switch gear of smaller size than heretofore.

Abstract: A lightning arrester monitor which consists of an oxygen gas sensor provided in a lightning arrester having a zinc-oxide-type element made of zinc oxide, the main component thereof, and other oxides added thereto, the oxygen gas sensor measures the oxygen concentration of the element which increases as degradation thereof goes on. The monitor makes it possible to assess degradation of the zinc-oxide-type element with ease, without requiring any complicated electrical circuit for detecting leakage current.

Abstract: A fault current interrupting disconnector, or fault disconnector, for a surge arrester operates to separate an electrical lead or ground lead wire from a damaged arrester and to interrupt the current flowing through the damaged arrester. The new fault disconnector includes an explosive charge, a tube of ablative material in a surrounding housing which co-acts with the tube to form a venting chamber, and a conductor extending through a portion of the chamber and through the tube. Excessive current heats and explodes the charge. The explosion pulls the conductor from an elongate connection, through the chamber portion and on through the tube; whereby arcing is first delayed, then is initiated in the chamber and then is drawn into and extinguished within the tube.

Abstract: A method and circuit are disclosed for detecting the state of a variable capacitor by comparator means whose threshold voltage is impressed on first plates of the variable capacitor and a reference capacitor having a capacitance between the minimum and maximum capacitances of the variable capacitor, and charging and discharging the second plates of the variable and reference capacitors by equal amounts in opposite senses. The voltage on the first plates of the capacitors then changes in a sense dependent on the relative capacitance values of the capacitors and is compared with the threshold voltage by the comparator means.

Abstract: The device includes two detectors of overvoltage (8, 9) each connected between a respective one of a pair of power line conductors (1, 2) and a respective input of an arrester (7). The outputs of the detectors are connected to an OR-gate (10) the output signal of which is applied to a threshold gate (12). The output of gate (12) is connected to a first monostable trigger (13) having a first time constant and controlling, through a latch gate (14), a bipolar insulating device (3, 4) isolating the load (90) from the power network. In order to achieve the automatic reconnection of the load after each perturbance, the output of the latch gate (14) is also connected to a second monostable trigger (16) having a second time constant higher than the first, and to the clock input of a counter (15) having its return-to-zero terminal connected at the output of the second monostable trigger. Preferably, an integrator (11) is connected between the OR-gate (10) and the threshold gate ( 12).

Abstract: An electrical, medium voltage, switching mechanism which includes a casing having an insulating material filling. In the casing, between a cable connection and a bus bar, a change-over switch, which can alternately switch between a phase contact and a ground contact, follows a load disconnector which is in the form of a vacuum switching tube. An axially displaceable shaft is provided which is displaceable relative to the load disconnector and is rotatable relative to the change-over switch. The bus bar passes through an insulator at right angles thereto. The associated through passage in the insulator is widened into a slot, the length of which permits the switching movements of the load disconnector. The insulator is divided into an insulator core and an insulator casing which is rotatably mounted on the insulator core.

Abstract: A plurality of breaking portions forming a vertically-disposed circuit breaker are connected in series and open and close the circuit within a gas-tight sealed enclosure. The enclosure is provided at its both sides with openings for connection of one and the other ends of the breaking portions, to which openings main bus bars and an insulated-led-out device are connected, respectively. The breaking portions each have a fixed contactor and a movable contactor, and the movable contactor is put into contact with or is separated from the fixed contactor by moving the movable contactor upward or downward under control of an operating device.