1174 results about "Tap changer" patented technology

A regulated power factor corrected power supply apparatus is provided. The apparatus includes an input rectifier circuit for receiving an input AC voltage and outputting a full-wave rectified DC voltage. A single-stage isolated buck-type converter is coupled with the input circuit. The converter circuit comprises an isolated buck-type converter circuit including an isolation transformer. An output rectifier and semiconductor tap switch are coupled to a secondary winding of the isolation transformer. The tap switch couples a larger portion of the secondary winding to an output bulk capacitor during the portions of the input sinewave half-cycle, which are low in amplitude. The tap switch enables the single-stage isolation buck-type converter to operate over a much larger portion of the input sinewave, but also allows the converter to operate at high-efficiency over the majority of the input sinewave.

A power conversion system includes an input terminal that is arranged to be connected to a voltage source; a transformer having a first winding connected to the input terminal and a second winding connected to an output terminal of the power conversion system, either the first winding or the second winding is provided with at least three taps that are arranged to divide the first winding or the second winding into at least two sub-windings; at least one tap switch connected to the at least two sub-windings; a control circuit connected to the at least one tap switch; and at least one switch connected to the at least one tap switch. The control circuit is arranged to control the at least one tap switch to control the turn ratio of the transformer.

A method of operating a tap changer of a transformer or a voltage regulator in a power grid includes obtaining a load forecast for a time period. An average voltage profile is determined for the time period based on the load forecast. The method further includes estimating tap positions of the tap changer for leveling the average voltage profile during the time period. Switching signal commands are provided to the tap changer based on the estimated tap positions.

“SYSTEM AND METHOD FOR MONITORING DISSOLVED GASES IN INSULATING OIL OF POWER TRANSFORMERS, REACTORS, ON-LOAD TAP CHANGERS, CURRENT TRANSFORMERS, POTENTIAL TRANSFORMERS, CONDENSIVE BUSHINGS AS WELL AS SIMILAR HIGH VOLTAGE EQUIPMENTS IMMERSED IN OIL”, remarkably consisting of a system that couples to an orifice for the insulating oil accessing, assuring to the monitoring system the access to an oil sampling with a good representativity of what is going on inside the high voltage equipment, besides allowing a simple and safe installation, and also presenting to the user several resources and interfaces.

The invention relates to an external hanging combined vacuum on-load tap switch, comprising a case, a tap selector, a switching means assembly, a transmission device, and one electric operation mechanism, wherein one lateral side wall of the case is provided with a connecting terminal connected with the coil tap of a transformer; the external side of the wall is provided with a first flange plate and is connected with a second flange plate of the transformer; the tap selector and the switching means assembly are arranged inside the case in parallel; and the electric operation mechanism is connected with the transmission device and drives the tap selector and the switching means assembly to achieve tapping and switching through the transmission device.

A method of measuring the characteristics of a transformer comprises the steps of determining the transformer turns ratio, switching the load tap changer from the current tap position to a subsequent tap position while determining a primary current and measuring the secondary voltage across the secondary side, determining the primary voltage across the primary side, and determining the characteristics of the transformer based on the determined transformer turns ratio, the determined primary current and the measured secondary voltage. Thereby, the static and dynamic characteristics of the transformer including a load tap changer can be determined.

The invention relates to a method for carrying out online monitoring on an operating state of a transformer OLTC (on-load tap-changer) and belongs to the field of signal monitoring. The method comprises the following steps of: acquiring a mechanical vibrating signal of a box wall of a transformer in real time; carrying out phase space reconstruction on the vibrating signal x(t) by using a delay coordinate method; determining a designated area V of a reconstructed phase space; calculating density distribution of space phase points; calculating a correlation coefficient rho of a space density curve before and after the OLTC actuates; if the correlation coefficient rho is more than 0.8, judging that the operating state of the OLTC is normal; and if the correlation coefficient rho is less than 0.8, judging that the operating state of the OLTC is abnormal. By carrying out real-time monitoring on the vibrating signal in the actuating process of the OLTC, efficient and accurate judgment on the working state of the transformer OLTC can be implemented. The method can be widely used for the field of online monitoring and fault diagnosis of various transformer OLTCs.

Provided is a method and device realizing load voltage regulation by a plurality of switch elements used by the regulating transformer and the reactor, each tap endpoint of the loading regulating transformer or the reactor voltage regulation winding is connected with the switch elements, a thermic element is connected between the tap changer and the switch element; or each tap endpoint of the regulating winding is connected with a current limiting branch composed of switch elements connected serially with the current limiting resistor or other current limiting elements and a direct passing branch composed of switch elements, the current limiting branch is paralleled with the direct passing branch; the switch element or the other end of the parallel circuit connected with the tap endpoint of the same phase voltage regulation winding are paralleled and educed; the device regulates the output voltage by controlling the make and break of different switch elements according to the detection of the voltage detection circuit.

The invention relates to a current online monitoring integrated system of an on-load tap changer. The current online monitoring integrated system comprises a current acquisition device, a receiving device and a terminal machine, and is characterized in that the current acquisition device is fixedly arranged on the side of the on-load tap changer; the receiving device is arranged on the side of a control room; the current acquisition device is connected with the receiving device through an optical fiber; and the receiving device is connected with the terminal machine through a converting station network. The current acquisition device transmits optical digital signals to the receiving device while electrical high and low voltage side insulation is carried out through an optical fiber; and the receiving device frames the received primary current waveform data and sends to the converting station network, and simultaneously provides analogue signal for outputting. The primary current work waveform of the on-load tap changer is monitored in an online and real-time manner, the running state of the on-load tap changer can be effectively monitored, and electrical failures and mechanical failures of the on-load tap changer are diagnosed in real time; and the system sends out alarms if the on-load tap changer is in failure.

The invention discloses an intelligent transformer, belongs to the field of power grid transformers, and relates to the intelligent transformer. The intelligent transformer comprises an oil immersed transformer (1), a master station (2), a circuit breaker (3) and an intelligent terminal controller (4), wherein the master station (2) is connected with the circuit breaker (3) and the intelligent terminal controller (4) through a communication interface respectively; and the intelligent terminal controller (4) is connected with a mutual inductor group (5) for detecting the three-phase four-wire state of a power grid, a temperature sensor (8) for detecting an oil temperature of the transformer, a pressure sensor (9) for detecting an oil-gas pressure of the transformer, an electronic tap-changer (6) and a reactive compensation system (7) for adjusting the efficiency of the power grid and stabilizing a voltage, and a safety valve (10) for emergency processing. The master station (2) monitors and controls various indicators of the operation of the transformer through the circuit breaker (3) and the intelligent terminal controller (4) according to the detection information of the intelligent terminal controller (4), so as to make the power grid safe and stable. The intelligent transformer has high performance, high reliability and low cost.

The invention relates to a power transformer load tap changer switching contact slap fault diagnosis method and device. The diagnosis method includes that: firstly, real-time monitoring is carried outon tap changer switching action process, in the monitored signal, the latter half of time domain signal major energy is selected, so as to avoid the energy maximum point in time domain signal; secondly, time-frequency transformation analysis is carried out; thirdly, spectral line of the signal, which is higher in amplitude at the range of 800-1000Hz in frequency domain, is determined through analysis; fourthly, comparing is carried out, if the spectral line is obviously amplified compared with the normal condition of the tap changer, the tap changer is in the switching contact slap fault. Theinvention has the advantages that: the found fault characteristic value can accurately reflect tap changer switching contact slap fault, characteristic is obvious, repeatability is good, and the method has universality on tap changers of the same type; the load tap changer contact slap fault diagnosis technology is simple in engineering realization, and a sensor is convenient in installation; anda microcomputer is adopted for detection, processing and diagnosis, performance is reliable, realization is convenient, and diagnosis conclusion is visual.

A selector switch assembly for a load tap changer includes a bevel gear coupled with a motor drive shaft. A shaft assembly is coupled with the bevel gear and a switch is provided for each phase. Each switch includes a helical gear fixed to the shaft assembly, a Geneva pinion gear engaged with the helical gear, a first Geneva gear wheel mounted on a first shaft moved by a first follower of the pinion gear, a first contact arm associated with the first Geneva gear wheel to rotate therewith, a second Geneva gear wheel mounted on a second shaft and moved by a second follower of the pinion gear, and a second contact arm associated with the second Geneva gear wheel so as to rotate therewith. The contact arms include contacts that engage fixed contacts that define tap positions of the load tap changer.

The invention discloses an active distribution network (ADN) voltage real-time fuzzy control method. The method comprises steps: according to the maximum and minimum values of feeder voltage uploaded by each feeder, the maximum voltage and the minimum voltage of the distribution system are put forward, if certain feeder voltage exceeds a threshold, a reactive power fuzzy controller FQC for DG (distributed generation) is started, and reactive power is injected or absorbed through the DG; and if the reactive power fuzzy controller FQC for the DG can not restore the voltage to a normal level and deltaVsys</=deltaVmax-deltaalpha, a transformer on-load tap changer fuzzy controller FOC is started, the transformer on-load tap changer OLTC completes a voltage regulating task, or otherwise, an FPC is started, and the deltaVsys is reduced, wherein the deltaalpha is an adjusting value of the tap changer. The main control unit of the invention has a simple control algorithm, the needed communication data are few, the calculation amount is small, the decision-making time is short, problems of over voltage and low voltage caused due to mutual action between the OLTC and the DG can be lessened, and the consumptive ability towards the DG by the ADN can be improved.

The present invention provides a transformer monitoring system and method. The transformer monitoring system comprises a gas in oil chromatography on-line monitoring unit, a micro water in oil monitoring unit, a temperature monitoring unit, a partial discharge monitoring unit, a grounding current on-line monitoring unit, a transformer and on-load tap changer vibration monitoring unit and a master station computer. The transformer monitoring system and method provided by the present invention can monitor and diagnose the faults of a transformer by various monitoring units and monitoring methods, thereby improving the monitoring accuracy.

A load tap changer (LTC) having a plurality of windings is coupled to one of the primary and secondary of a power transformer in order to regulate the output voltage of the transformer. The LTC includes a plurality of taps physically and electrically connected to and along the windings and a contacting element is selectively moved along the taps to increase or decrease the output voltage of the transformer. The power transformer and the LTC windings are placed in a main tank and the taps are placed in an LTC tank. The temperature in the main tank and the temperature in the LTC tank are monitored by means of first and second temperature probes whose outputs are used to sense the temperature differential (T_DIFF) between the main tank and the LTC tank and to determine if the LTC tank temperature exceeds the main tank temperature for a period of time exceeding a specified time period. Also included is circuitry for sensing the rate of change of T_DIFF and determining if it exceeds a predetermined value.

The invention provides a method for measuring dynamic voltage stability margin index, while the dynamic voltage stability margin index is the margin to the voltage collapse point of a power system which load increase slowly in a certain speed; the dynamic voltage stability margin index considers that the system is affected by the dynamic components such as the on-load tap changer (ULTC) and the over excitation limit of engines. The method can calculate the dynamic margins of the system which load increases in various types such as single node, regional or full-network type, to provide a visual measurement presenting the distance between the prior operation point of the system and the voltage collapse point, while the distance and the dynamic margin have linear relationship. Therefore, the dynamic margin index has high practical values.

This invention applies a combination structure of two three-phase iron core and double winding by switching low voltage side hexagon to regulate the winding or high voltage side six starlike ones regulate the level, so makes the voltage phasor relatively zigzag shift between the winding of the regulated sore and the host core and realizes on-load voltage regulation and the auxiliary voltage regulation by way of compensation within capacitors. It has the advantages of low cost of regulation devices, small volume of tap switching and high power factor, which is suitable for producing new type of on-load regulation voltage transformer and the reform.

Disclosed are an interline nondestructive single-phase diverter and a design method and a control method thereof. The diverter comprises an on-load tap-changer, a diverter transformer, a voltage dividing transformer, a control motor, a microprocessor, two selector switches and a temperature sensing unit. The diverter is mounted between two guide lines. An input end of the diverter is connected with inner conductors and a first selector switch close to electricity load, and an output end of the diverter is connected with inner conductors, outer conductors and a second selector switch close to asupply end power source in the next section. The diverter transformer and the voltage dividing transformer are boosting transformers, and according to differences in structures, the diverter transformer is a duplex-winding diverter transformer or a self-coupling diverter transformer, and the voltage dividing transformer is a duplex-winding voltage dividing transformer or a self-coupling voltage dividing transformer. By means of calculating a coil turn ratio of the transformers, the selector switches are controlled by the microprocessor to enable current of the conductors to exactly meet requirement on ice resisting and melting, and the current and ice resisting and melting can be controlled precisely. The interline nondestructive single-phase diverter can work under a normal power transmission mode and an ice resisting and melting mode, and is simple and reliable to operate.

The invention discloses a method for automatically measuring a direct-current resistor, a short-circuit impedance, an on-load switch and a non-load voltage ratio of a transformer. In the measurement process, the opening-and-closing status of a high-pressure switch can be controlled so as to achieve the status of a transformer winding in the measurement process, and the status is pressurization or an open circuit or a short circuit or grounding. The current measuring item is selected by controlling a multi-way selection switch, and the item is the direct-current resistor or the on-load tapping switch or the short-circuit impedance or the non-load voltage ratio. The method can achieve automatic measurement of the direct-current resistor, the on-load tapping switch, the non-load voltage ratio and the short-circuit impedance of the power transformer, the winding status is automatically switched in the whole measurement process, manual intervention is not required, the measurement error can be reduced, working intensity can be relieved, and working efficiency is improved.