248 results about "Residual-current device" patented technology

A loop impedance meter is provided for testing an A.C. electrical mains supply. The meter comprises an electronic control circuit for connecting a load resistance intermittently between the A.C. mains supply terminal and the earth terminal to measure the potential difference between those terminals and to provide an indication of the loop impedance of the A.C. mains supply from that potential difference. The control circuit is arranged to allow a train of short pulses of current to flow through the load resistance and the loop, the pulse train beginning its sequence with a first train of pulses for preconditioning any residual current device-present in the loop to temporarily desensitize it. The first train of pulses is followed by one or more measurement pulses, the pulses of the first train being of generally increasing width.

The invention relates to a generating set sub-synchronous oscillation suppression method adopting a full-controlled variable current device. The method uses the variable quantity of a rotating speed signal of a generating set as a control quantity, and performs filter, phase shift, proportional amplification and operation processing on the variable quantity of the rotating speed signal to acquire a control signal for controlling a variable current power unit by using a voltage synchronization signal as standard, then the full-controlled variable current device generates a sub-synchronous model modulation current, and the current affects the rotating speed of the generating set through a power transmission unit so as to achieve the aim of suppressing the sub-synchronous oscillation of the generating set. A controller comprises a plurality of signal processing subunits and a main control subunit, wherein each signal processing subunit comprises a filter module, a phase shift module, a proportional amplification module and an operation module; and the main control subunit accomplishes the control for the full-controlled device. The method can effectively suppress the sub-synchronous oscillation problem of a power grid system, has high response speed and high tracing precision, and can greatly improve the stability and reliability of a power grid.

The invention discloses an RCD (Residual Current Device) detection device. A detection circuit in the detection device can generate a simulation drain current on the basis of a first control signal output by a controller, and the processed simulation drain current is output to the controller, a differential current transformer can output a drain current obtained in the detection to a signal processing unit which can process and output the drain current to the controller, a trip circuit can generate a simulation voltage based on a second control signal output by the controller and can output the simulation voltage to the controller and a tripping device, and the controller can determine whether the differential current transformer and/or the signal processing unit has faults or not according to the comparison results of the simulation drain current and the drain current, and determine whether the trip circuit and/or the tripping device has faults or not according to the comparison results of the attenuation ratio of the simulation voltage with a preset attenuation ratio, cue signals denoting the detection results can be output to a detection result cue unit, and the detection result cue unit can output the detection results according to the obtained cue signals. The invention further discloses an RCD detection method. By adopting the RCD detection device and the detection method provided by the invention, an RCD (Residual Current Device) can be detected in the case of the connection of a circuit breaker with a power grid.

The invention relates to a method and device for flexibly identifying residual current-type electrical fire on line. The method comprises the following steps: arranging a residual current mutual inductor in a power transmission and supply circuit of a low-voltage power distribution system; obtaining an instantaneous value irz of lumped residual current in the circuit as well as waveform which areacquired by the mutual inductor through a power supply branch residual current and other signal detection unit; and according to the characteristics such as abrupt change, discontinuity and nonlinearity of a spot-heat agglomeration residual current instantaneous value ird, separating and extracting ird from irz by adopting a modern information processing technology, and calculating an effective value Ird of ird so as to identify whether potential electrical fire danger exists according to the size of Ird. The on-line identification device consists of three parts such as a residual current signal processing unit, the power supply branch residual current and other signal detection unit and an output execution unit. By adopting the residual current-type flexible on-line electrical fire identification method and device, the features of the potential electrical fire danger caused by electric arc grounding faults can be accurately extracted, normal residual current and abnormal residual current can be correctly identified, and alarm failure and false alarm can be avoided.

The invention provides an improved residual current device (RCD) buffer circuit applied to a direct tandem type insulated gate bipolar translator (IGBT). The improved RCD buffer circuit comprises an RCD buffer unit, a voltage sampling module, a comparator module, a pulse generation unit and an auxiliary switch unit. The RCD buffer unit comprises a resistor R, a diode D and a capacitor C. The resistor R is connected with the diode D in parallel, then connected with the capacitor C in series, and then connected with a collector electrode end and an emitting electrode end of the IGBT. The voltage sampling module divides the voltage of the collector electrode end and the emitting electrode end of the IGBT, and the comparator module compares the divided voltage of the two ends of the IGBT and a preset reference level. And input end of the pulse generation unit is connected with an output end of the comparator module. According to the improved RCD buffer circuit applied to the direct tandem type IGBT, when overvoltage is detected, the pulse generation unit generates short-time pulses to control and assist turning-on and turning-off of the IGBT so as to realize short-time leakage of overvoltage energy, the overvoltage on two ends of the IGBT can be quickly reduced to a normal range, and loss is greatly reduced.

The invention provides a method and a device for monitoring and alarming residual current, and a detection controller. The method comprises the following steps of: acquiring a three-phase load current value and a residual current value of a monitored loop; generating and storing the residual current relative value of each acquisition time point according to the acquired load current value and residual current value; performing statistical analysis on a plurality of residual current relative values in a preset time interval, and generating and storing the statistical parameters of the plurality of residual current relative values; generating an alarm threshold value of a monitoring time point according to the residual current relative values and the statistical parameters which are stored before the monitoring time point; and monitoring and alarming the residual current of the monitored loop according to the generated alarm threshold value. By the method and the device for monitoring and alarming the residual current, and the detection controller, a leakage alarm and a false alarm caused by the conventional fixed alarm threshold value can be avoided.

The invention discloses a remote intelligent residual current monitoring and protection system, which comprises a three-phase residual current protection device, single-phase residual current protection devices, a detection data/control signal transmitting device, a monitoring centre and a monitoring unit, wherein the three-phase residual current protection device is arranged on a three-phase main power line outlet; the single-phase residual current protection devices are arranged on three phases of power supply lines respectively; the monitoring unit is connected with the monitoring centre and also connected with a first stage of residual current protection device; the monitoring centre determines the upper limit value of split-phase/single-phase residual current of each phase of power supply circuit and monitors/analyzes the related detection data of a next stage of residual current protection device in real time; when the residual current on a certain phase of line exceeds the upper limit value, an alarm is sent; the amplitude of the residual current of each phase of line is monitored and adjusted to ensure the balance of the three-phase residual current; and the current of the neutral earth line of a power transformer is reduced and frequent tripping of the first stage of residual current protection device is prevented, so that the operating ratio and the reliability of the power grid are improved.

An automatic reset and self-test device, particularly for residual current operated circuit breakers and the like, comprising a containment body which can be coupled to an electrical device, such as a residual current operated circuit breaker provided with main contacts and secondary or auxiliary contacts, the containment body including a drum which is kinematically associated with the control for opening and closing the main contacts of the circuit breaker; characterized in that it comprises an electric motor suitable to drive a gear train by means of a worm screw, turning round in one direction only, for closing the main contacts and the secondary contacts.

A magnet core (1) that is suitable for use in a fault current circuit breaker and that is made of a helically wound, magnetically soft band has a top (4) and a bottom (5), the top (4) and the bottom (5) being formed by side surfaces (16) of the magnetically soft band. The magnet core (1) is fixed in a protective housing (6), and there is a contact cement (11) between the bottom (5) of the magnet core (1) and an inside wall (10) of the housing for fixing the magnet core (1).

The invention discloses a grounding line selecting and ground fault section positioning method for an arc suppression coil. According to the method, when a neutral point of a main transformer is grounded in a one-phase mode through the arc suppression coil, a residual current and displacement voltage are generated, and the residual current is an inductive current in the overcompensation process, is a capacitance current in the undercompensation process and is equal to zero in the full compensation process to form a ground fault line; after grounding line selecting, the ground fault section positioning method includes the steps that on a grounding line, a section switch which the residual current does not flow through detects i0 as the capacitance current, the reactive power is a positive value, and the section between the switch which the residual current flows through and an adjacent switch which the residual current does not flow through serves as a ground fault section; if the residual current is detected in one line, the residual current and the small ground capacitance current are not detected in other lines, at the moment the line with the residual current serves as the ground line, and the section with the residual current and the adjacent section with the small ground capacitance current serve as the ground fault sections.

A fault in a DC power source, such as a battery string or a string of photovoltaic cells, is identified by detecting a change in an AC component of a residual current of the DC power source. In some embodiments, the DC power source is coupled to at least one DC bus and he methods further include generating an AC voltage on the at least one DC bus. For example, the DC power source may be coupled to a modulated DC bus of an uninterruptible power supply (UPS) system comprising an inverter having an input coupled to the DC bus. The inverter may be configured to generate an AC output voltage and the AC component has a frequency that is a harmonic of a fundamental frequency of the AC output voltage, such as a third harmonic of the fundamental frequency of the AC output voltage.

The invention provides a control device for residual current in a low voltage power grid, and comprises a residual current controller, a zero line grounding detector, an overvoltage detector, a zero-sequence current detection controller, a time controller, an actuating member controlled by the time controller, and a load switch controlled by the actuating member, wherein the zero line grounding detector, the overvoltage detector and the zero-sequence current detection controller are connected with the time controller, which comprises a time relay; and the residual current controller comprises a potentiometer, a residual current relay, a closed contactor of the time replay in the time controller and a normally open contactor and a normally closed contactor of the residual current relay. The device has the advantages of scientific designing, low cost, high power supply reliability, and assurance of personal safety, and overcomes the shortcomings of the existing residual current protector, including frequently tripping and non-detectable line insulation during operation at the same time.

The invention relates to comprehensive road surface deicing equipment. Comprehensive road surface deicing equipment, including a mechanical deicing device, a deicing margin control device for controlling the amount of ice removed by the mechanical deicing device to leave a residual ice layer on the road surface, and a device for dissolving the ice layer by heat energy The thermal deicing device that melts the remaining ice layer defines that the comprehensive road surface deicing equipment moves forward when in use, and the thermal deicing device is arranged behind the mechanical deicing device. The deicing margin control device can be used to control the amount of ice removed by the mechanical deicing device, so as to leave a residual ice layer with a set thickness on the road surface, so as to prevent the mechanical deicing device from directly contacting the road surface and causing damage to the road surface or the device Self-damage; and the remaining ice layer can be melted by the thermal deicing device arranged at the rear of the mechanical deicing device, so as to achieve the purpose of no ice layer remaining. The contradiction between high deicing efficiency and energy saving.

A power control apparatus comprises a transducer having an output (12,13) which is connected to a remotely activated device (25) mounted in a mains consumer unit (14). When a predefined parameter is detected, the device (25) is activated to connect a load (29) between the switched live output (18) of a residual current device RCD (15) and the neutral input (17) thereof, thereby creating an imbalanced current flow on the live and neutral output terminals (18,19) of the RCD (15) which causes contacts (20,21) inside the RCD (15) to disconnect the supply to an appliance circuit (22).

The invention relates to a direct current bus quick discharge circuit of an explosion-proof converter. The circuit comprises a control power supply, a controllable switch type device, a power discharge resistor and an RCD (Residual Current Device) resistance-capacitance absorbing loop, wherein the control power supply is connected with the control end of the controllable switch type device; the power discharge resistor is connected in series with a contact switch of the controllable switch type device and then is connected to the positive end and the negative end of a direct current bus pole plate which is required to be discharged and comprises a high capacitance support; and the RCD resistance-capacitance absorbing loop is connected in parallel to two ends of the contact switch of the controllable switch type device. After a system is powered down, on and off of the contact switch of the controllable switch type device are controlled by controlling power-on and power-down of the control end of the controllable switch type device, so that quick discharge of a direct current bus capacitor is realized. The circuit has the advantages that energy stored by the direct current bus capacitor can be quickly reduced to below 0.2mJ in 15 minutes; the system has high working stability, reliability and safety; the maintenance efficiency and the repair efficiency of the system are increased; the volume of the equipment is reduced; and the system cost is reduced.

The invention provides a residual current protecting device. The residual current protecting device comprises a first current transformer, a second current transformer, a switching unit, a first residual current detecting module and a second residual current detecting module, wherein the second residual current detecting module comprises a first detecting unit and a second detecting unit; the switching unit is used for switching the residual current protecting device between a first state and a second state, so that, in the first state, the coil of the first current transformer and the coil of the second current transformer can be connected in series and both ends of the formed series-connected coil set can be connected with the two input electrodes of the first residual current detecting module, and in the second state, both ends of the coil of the first current transformer can be connected with the first detecting unit and both ends of the coil of the second current transformer can be connected with the second detecting unit. The residual current protecting device can enhance the sensitivity under the premise of no increase in size.

The residual current device (2; 200) associable to an electric circuit-breaker (1), the residual current device (2;200) comprising: interconnection electric terminals (22) suitable to establish, by co-operating with respective electric terminals of the circuit-breaker (1) that are accessible through a first face (6) of the latter, an electrical connection between the device (2;200) and the electric circuit-breaker (1); and mechanical coupling means (15,16) suitable to allow a mechanical interaction between the device (2;200) and the circuit-breaker (1) through a second face (12) perpendicular to said first face (6). The device (2;200) comprises first (20,21;221) and second (24;220) parts, which are pivotally connected to each other and carry said interconnection electric terminals (22) and said mechanical coupling means (15,16), respectively.

The invention discloses a residual current protector, which comprises a switch device, a residual current transformer and an electronic controller, wherein the electronic controller detects a network voltage, generates a simulated residual current in a power network and controls off and on of the switch device on the basis of an actual residual current, sensed by the residual current transformer, in the power network before the simulated residual current is generated, and the total residual current and network voltage, sensed by the residual current transformer, in the power network after the simulated residual current is generated. By the technical scheme disclosed by the invention, inspection of the residual current protection function can be achieved under the condition of not interrupting power supply; the protection capability of the residual current protector is ensured; and the burden of a user is relieved.