CN201623436U - DC ice melting device that can be reused as TSC - Google Patents

Abstract

The utility model discloses a DC deicing device that can be reused as a TSC, which is composed of a circuit breaker, an incoming line reactor, a DC smoothing reactor, a compensation capacitor, a plurality of isolating switches and a power switch module. A single power switch module consists of voltage equalizing resistors, damping resistors, damping capacitors and thyristors. By changing the switch states of G1-G8, the device can be used as a fully-controlled rectifier bridge for DC ice melting according to site needs, and can also be used as a thyristor switching capacitor TSC for dynamic reactive power compensation. The utility model expands the single function of the DC ice-melting device, so that it can perform dynamic reactive power compensation in the non-ice-melting state, avoiding the idleness of the device in most of the time, and improving the utilization rate and cost performance of the equipment. On the other hand, since the device is always in operation as a reactive power compensation device under normal circumstances, compared with the periodic use of a single ice-melting device, the utility model is relatively simpler in daily maintenance and testing, and has higher reliability.

Description

DC ice melting device that can be reused as TSC

technical field

The utility model relates to the technical field of power electronics application equipment, in particular to a DC ice-melting device that can be reused as a TSC.

Background technique

Ice and snow accumulation on transmission lines will cause accidents such as line tripping, disconnection, pole down, conductor galloping, insulator flashover, communication interruption, and large-scale power outages. Europe, America, Asia and other countries have caused safety accidents due to icing of power transmission lines, which have brought huge economic losses, and our country has also suffered greatly. Therefore ice and snow disasters have become a common problem faced by power grids in many countries around the world. Since the 1940s, the threat of freezing disasters has been a major technical problem that power systems, industry and academia have been trying to deal with for more than half a century. Research on feasible ice-melting technology and equipment is of great theoretical and practical significance. value items.

The ice-melting technology that converts electrical energy into heat energy is one of the main deicing methods. Judging from the current technical level at home and abroad, "AC short circuit ice melting" and "DC current ice melting method" are the two most mature and feasible ice melting methods. means. Compared with "changing the distribution of power flow to melt ice" and "with load ice melting method", the use of "AC short-circuit ice melting method" and "DC current ice melting method" needs to adjust the line to the outage state, although part of the transmission capacity is lost , but it can completely melt the icing on the line to ensure the safe and stable operation of the power grid.

The transmission line adopts the traditional AC short-circuit ice-melting method. Due to the limitation of the maximum allowable current of the wire, it is usually necessary to connect multiple lines in series for impedance matching, resulting in power failure of multiple lines, and the series connection of multiple lines will reduce the reactance of the ice-melting line. Greatly increased, the required ice melting capacity is also greatly increased, which is not conducive to the power balance in the grid. Different from the AC ice melting method, under certain environmental conditions, the power supply capacity required for DC ice melting depends only on the unit DC resistance and wire length of the ice melting line, and is not affected by the AC reactance of the line. The required power supply capacity can be greatly improved. reduce. On the basis of obtaining better cost performance, according to the actual situation of ice melting in the power grid, it can be designed as a mobile or fixed DC ice melting equipment, which is more flexible in use and operation; on the premise of stable AC power supply, the DC ice melting method There are fewer lines in series, which reduces the loss of power failure caused by ice melting, which is conducive to the stable and safe operation of the power grid. It can avoid the shortcomings of the previous AC ice melting technology, such as impedance matching difficulties, many operations during ice melting, and difficult load transfer, etc., and realize the whole network. Simultaneous ice melting of multiple lines and multiple substations can better meet the needs of current grid 220kV and below substations and lines for ice melting.

Considering that the icing of the line is mainly caused by climate reasons, the use of the ice melting device has a strong periodicity and can only be effective in a specific time period in winter. If the function of the ice-melting device is relatively single, its cost performance will be very poor, which is not conducive to popularization and application. At the same time, due to long-term power failure, the reliability of the device will decline, and there will be certain difficulties in its daily maintenance.

Contents of the invention

The purpose of this utility model is to provide a DC ice-melting device that can be reused as a TSC. According to the needs of the site, it can be used as a fully-controlled rectifier bridge for line DC ice-melting, and can also be used as a thyristor switching capacitor TSC for dynamic Reactive power compensation, thus effectively improving the utilization rate of equipment.

The utility model is realized through the following scheme: including a circuit breaker, an incoming line reactor, a DC smoothing reactor, a compensation capacitor, a first three-phase isolating switch, a second three-phase isolating switch, a third three-phase isolating switch, a fourth and a third The phase isolating switch, the fifth three-phase isolating switch, the sixth three-phase isolating switch, the seventh three-phase isolating switch, the eighth three-phase isolating switch and the first power switch module, the second power switch module, and the third power switch module , the fourth power switch module, the fifth power switch module, and the sixth power switch module, the circuit breaker is directly connected to the three-phase power supply, and then connected to the line reactor, and then connected to the power switch module Three-phase bridge arm connection; the A phase of the first three-phase isolating switch is between the A phase and the B phase upper bridge arm of the three-phase bridge arm, and the B phase is between the B phase and the C phase upper bridge arm of the three-phase bridge arm , Phase C is connected to the positive output terminal of the three-phase bridge arm; phase A of the second three-phase isolating switch is connected in parallel to the phase A bridge arm of the three-phase bridge, phase B is connected in parallel to the phase B bridge arm of the three-phase bridge, and phase C is connected to the phase B bridge arm of the three-phase bridge in parallel. The C-phase bridge arm of the three-phase bridge is connected in parallel; the A-phase of the third three-phase isolating switch is between the A-phase and B-phase lower bridge arms of the three-phase bridge arm, and the B-phase is under the B-phase and C-phase of the three-phase bridge arm Between the bridge arms, the C phase is connected to the negative output terminal of the three-phase bridge arm; the fourth three-phase isolating switch is connected to the negative pole of the lower bridge arm of the three-phase bridge, and then connected to the three-phase compensation capacitor, and the other three-phase compensation capacitor Three-phase short circuit at one end; phase C of the first three-phase isolating switch is connected to the DC smoothing reactor, the other end of the DC smoothing reactor is connected to the first output terminal and the second output terminal of the positive output, and the third three-phase Phase C of the isolating switch is connected to the first negative output terminal and the second negative output terminal of the output negative pole, wherein the second output terminal is connected to the positive pole through the seventh three-phase isolating switch, and the first negative output terminal is connected to the positive pole through the eighth three-phase isolating switch. Negative poles are connected, the first output terminal is connected to the first negative pole output terminal through the fifth three-phase isolating switch, and the second output terminal is connected to the second negative pole output terminal through the sixth three-phase isolating switch; when melting ice, the positive pole has Two output terminals: the first output terminal and the second output terminal, the negative pole has two output terminals: the first negative pole output terminal and the second negative pole output terminal, wherein the second output terminal is connected to the positive pole through the seventh three-phase isolating switch, The first negative output terminal is connected to the negative pole through the eighth three-phase isolating switch, the first output terminal is connected to the first negative output terminal through the fifth three-phase isolating switch, and the second output terminal is connected to the second negative output terminal through The sixth three-phase isolating switch is connected; A, B, and C three-phase lines are respectively connected to: the first output terminal, the second output terminal and the first negative output terminal, through the on-off selection of the fifth to eighth three-phase isolating switches Each phase circuit that needs to melt ice; when the fifth three-phase isolating switch and the sixth three-phase isolating switch are closed, and when the seventh three-phase isolating switch and the eighth three-phase isolating switch are off, mainly melt the B-phase line; the sixth three-phase isolating switch switch, the eighth three-phase isolating switch is closed, the fifth three-phase isolating switch, the seventh three-phase isolating phase isolating switch, sixty-three When the phase isolating switch is disconnected, it mainly fuses the C-phase line; when the first three-phase isolating switch and the third three-phase isolating switch on the bridge arm are closed and the second three-phase isolating switch and the fourth three-phase isolating switch are disconnected, the device It operates as a fully controlled 6-pulse rectifier bridge to provide DC ice melting power; when the second three-phase isolating switch and the fourth three-phase isolating switch on the bridge arm are closed and the first three-phase isolating switch and the third three-phase isolating switch are closed When disconnected, the device operates as a thyristor switched capacitor for dynamic compensation of reactive power.

Each power switch module described in the utility model is composed of a voltage equalizing resistor, a damping resistor, a damping capacitor and a thyristor. 1 to 15 power switch modules are connected in series to form a single-phase bridge arm. The voltage equalizing resistor and the thyristor are connected in parallel for static voltage equalization and damping. The resistor and the damping capacitor are connected in parallel with the thyristor after being connected in series.

The incoming line reactor described in the utility model adopts an air-core reactor.

The beneficial effects of the utility model are: the single function of the DC ice melting device is expanded, so that it can perform dynamic reactive power compensation in the non-ice melting state, avoiding the idleness of the device in most of the time, and improving the utilization rate of the equipment and cost-effective. On the other hand, since the device is always in operation as a reactive power compensation device under normal circumstances, compared with the periodic use of a single ice-melting device, the utility model is relatively simpler in daily maintenance and testing, and has higher reliability.

Description of drawings

Fig. 1 is a structural schematic diagram of the main circuit of the utility model.

Fig. 2 is a schematic diagram of the utility model for melting ice of a phase A line when the utility model operates as a direct current ice melting device.

Fig. 3 is a schematic diagram of melting ice of the B-phase line when the utility model operates as a direct current ice melting device.

Fig. 4 is a schematic diagram of melting ice of a C-phase line when the utility model operates as a direct current ice melting device.

Fig. 5 is a schematic diagram of the utility model when operating as a dynamic compensation device TSC.

Detailed ways

The technical solution adopted by the utility model to solve the technical problem is: the device consists of a circuit breaker, an incoming line reactor, a DC smoothing reactor, a compensation capacitor, a plurality of isolating switches and a three-phase bridge arm composed of a plurality of power switch modules constitute.

The single power switch module described in the utility model is composed of a voltage equalizing resistor, a damping resistor, a damping capacitor and a thyristor, and 1 to 15 power switch modules are connected in series to form a single-phase bridge arm. The voltage equalizing resistor is connected in parallel with the thyristor for static voltage equalization, and the damping resistor and the damping capacitor are connected in parallel with the thyristor to eliminate dynamic overvoltage.

The line reactor described in the utility model adopts an air-core reactor, which acts as a filter when melting ice to protect the normal operation of the thyristor, and forms a capacitive compensation branch together with a compensation capacitor during reactive power compensation to eliminate switching time flow.

The utility model expands the single function of the DC ice-melting device so that it can perform dynamic reactive power compensation in the non-ice-melting state, avoiding the idleness of the device in most of the time, and improving the utilization rate and cost performance of the equipment. On the other hand, since the device is always in operation as a reactive power compensation device under normal circumstances, compared with the periodic use of a single ice-melting device, the utility model is relatively simpler in daily maintenance and testing, and has higher reliability.

Detailed ways

The utility model will be described in detail below in conjunction with the embodiments and with reference to the accompanying drawings.

Referring to Fig. 1, shown is the utility model main circuit structure schematic diagram. The device consists of circuit breaker DL1, line reactor L1, DC smoothing reactor L2, compensation capacitor C1, first three-phase isolating switch (G1), second three-phase isolating switch (G2), third three-phase isolating switch ( G3), the fourth three-phase isolating switch (G4), the fifth three-phase isolating switch (G5), the sixth three-phase isolating switch (G6), the seventh three-phase isolating switch (G7), the eighth three-phase isolating switch ( G8) and the first power switch modules THAZ1-THAZn, the second power switch modules THAF1-THAFn, the third power switch modules THBZ1-THBZn, the fourth power switch modules THBF1-THBFn, the fifth power switch modules THCZ1-THCZn, the A three-phase bridge arm composed of six power switch modules THCF1~THCFn. The incoming lines of A, B, and C are connected to the three-phase AC power supply through the circuit breaker DL1, connected in series with the incoming line reactor L1, the circuit breaker DL1 is directly connected to the three-phase power supply, and then connected to the incoming line reactor L1, and then connected to the power switch The three-phase bridge arm connection composed of modules; the A phase of the first three-phase isolating switch G1 is between the A phase and the B phase upper bridge arm of the three-phase bridge arm, and the B phase is on the B phase and the C phase of the three-phase bridge arm Between the bridge arms, the C phase is connected to the positive output terminal of the three-phase bridge arm; the A phase of the second three-phase isolation switch G2 is connected in parallel with the A-phase bridge arm of the three-phase bridge, and the B phase is connected to the B-phase bridge arm of the three-phase bridge Parallel connection, C-phase and C-phase bridge arm of the three-phase bridge are connected in parallel; A-phase of the third three-phase isolating switch G3 is between the A-phase and B-phase lower bridge arm of the three-phase bridge arm, and B-phase is at the end of the three-phase bridge arm Between the lower bridge arms of the B phase and the C phase, the C phase is connected to the negative output terminal of the three-phase bridge arm. The fourth three-phase isolating switch G4 is connected to the negative pole of the lower arm of the three-phase bridge, and then connected to the three-phase compensation capacitor C1, and the other end of the three-phase compensation capacitor C1 is short-circuited in three phases. Phase C of the first three-phase isolation switch G1 is connected to the DC smoothing reactor L2, and the other end of the DC smoothing reactor L2 is connected to the first output terminal ZO1 and the second output terminal ZO2 of the positive output, and the third three-phase isolation Phase C of the switch G3 is connected to the two output terminals of the output negative pole, the first negative pole output terminal PO1 and the second negative pole output terminal PO2, wherein the second output terminal ZO2 is connected to the positive pole through the seventh three-phase isolating switch G7, and the first negative pole output terminal PO1 is connected to the negative pole through the eighth three-phase isolating switch G8, the first output terminal ZO1 is connected to the first negative output terminal PO1 through the fifth three-phase isolating switch G5, and the second output terminal ZO2 is connected to the second negative output terminal PO2. are connected through the sixth three-phase isolating switch G6. As an ice melting device, the positive pole has two output terminals ZO1 and ZO2, and the negative pole has two output terminals PO1 and PO2, wherein the second output terminal ZO2 is connected to the positive pole through the seventh three-phase isolating switch G7, and the first negative pole output terminal PO1 is passed through The eighth three-phase isolating switch G8 is connected to the negative pole, the first output terminal ZO1 is connected to the first negative output terminal PO1 through the fifth three-phase isolating switch G5, and the second output terminal ZO2 is connected to the second negative output terminal PO2 through The sixth three-phase isolation switch G6 is connected.

Referring to FIG. 2 , it is a schematic diagram of the utility model for melting ice of a phase A line when the utility model operates as a direct current ice melting device. At this time, the second three-phase isolating switch G2, the fourth three-phase isolating switch G4, the fifth three-phase isolating switch G5, the seventh three-phase isolating switch G7 are disconnected, the first three-phase isolating switch G1, the third three-phase isolating switch G3, the sixth three-phase isolation switch G6, and the eighth three-phase isolation switch G8 are closed. The incoming lines of devices A, B, and C are connected to the three-phase AC power supply through the circuit breaker DL1, and L1 acts as a line reactor to filter to better ensure the normal operation of the thyristor. The power switch module constitutes a six-pulse fully-controlled rectifier bridge, which provides DC ice-melting current required for line melting through real-time control of thyristor switching and smoothing. Among them, the first power switch module THAZ1~THAZn and the second power switch module THAF1~THAFn The upper and lower bridge arms of phase A are respectively formed, the third power switch modules THBZ1-THBZn and the fourth power switch modules THBF1-THBFn respectively form the upper and lower bridge arms of phase B, the fifth power switch modules THCZ1-THCZn and the sixth power switch modules THCF1-THCFn They respectively constitute the upper and lower bridge arms of phase C. L2 is connected to the DC output terminal of the rectifier bridge as a smoothing reactor to filter out the ripple on the DC side and ensure the stability and freewheeling of the ice-melting power supply. The A, B, and C three-phase lines that need to be melted are connected to the first output terminal ZO1, the second output terminal ZO2 and the first negative output terminal PO1 of the DC output end of the device respectively, and the three phases on the opposite side are short-circuited. At this time, it is equivalent to that the phase A line is connected to the positive pole of the DC output alone, and the phase B and phase C lines are connected to the negative pole of the DC output in parallel. During the ice melting process, phase A is the main melting phase, and the current passing through it is twice that of phase B and phase C.

Referring to FIG. 3 , it is a schematic diagram of the utility model for melting ice of a phase B line when the utility model operates as a direct current ice melting device. At this time, the second three-phase isolating switch G2, the fourth three-phase isolating switch G4, the seventh three-phase isolating switch G7, the eighth three-phase isolating switch G8 are disconnected, the first three-phase isolating switch G1, the third three-phase isolating switch G3, the fifth three-phase isolation switch G5, and the sixth three-phase isolation switch G6 are closed.

At this time, it is equivalent to that the B-phase line is connected to the DC output positive pole alone, and the A-phase and C-phase lines are connected to the DC output negative pole in parallel. During the ice-melting process, phase B is the main ice-melting phase, and the current passing through it is twice that of phase A and phase C. Others are the same as those described in Figure 2.

Referring to FIG. 4 , it is a schematic diagram of the utility model for melting ice of a C-phase line when the utility model operates as a direct current ice melting device. At this time, the second three-phase isolating switch G2, the fourth three-phase isolating switch G4, the fifth three-phase isolating switch G5, the sixth three-phase isolating switch G6 are disconnected, the first three-phase isolating switch G1, the third three-phase isolating switch G3, the seventh three-phase isolation switch G7, and the eighth three-phase isolation switch G8 are closed.

At this time, it is equivalent to that the phase C line is connected to the positive pole of the DC output alone, and the phase A and phase B lines are connected to the negative pole of the DC output in parallel. During the ice-melting process, phase C is the main melting phase, and the current passing through it is twice that of phase A and phase B. Others are the same as those described in Figure 2.

Referring to FIG. 5 , it is a schematic diagram of the utility model when it operates as a dynamic compensation device TSC. At this moment, the first three-phase isolating switch G1 and the third three-phase isolating switch G3 are opened, and the second three-phase isolating switch G2 and the fourth three-phase isolating switch G4 are closed. The incoming lines of devices A, B, and C are connected to the three-phase AC power supply through the circuit breaker DL1. The incoming line reactor L1 and the compensation capacitor C1 together form a capacitive compensation branch. L1 is used to limit the inrush current generated when the capacitive branch is switched. , C1 is used to provide capacitive compensation reactive power. The power switch module constitutes a three-phase electronic switch. By controlling the opening and closing of the thyristor in real time, the three-phase compensation branch can be switched quickly and repeatedly. The first power switch module THAZ1~THAZn and the second power switch module THAF1~THAFn are connected in antiparallel In phase A, the third power switch modules THBZ1~THBZn and the fourth power switch modules THBF1~THBFn are connected in antiparallel to phase B, and the fifth power switch modules THCZ1~THCZn and sixth power switch modules THCF1~THCFn are connected in antiparallel to phase C .

Claims (3)

1. DC de-icing device that reusable is TSC, it is characterized in that: comprise circuit breaker (DL1), inlet wire reactor (L1), dc flat-wave reactor (L2), compensation condenser (C1), first three-phase isolation switch (G1), second three-phase isolation switch (G2), the 3rd three-phase isolation switch (G3), the 4th three-phase isolation switch (G4), the 5th three-phase isolation switch (G5), the 6th three-phase isolation switch (G6), the 7th three-phase isolation switch (G7), the 8th three-phase isolation switch (G8) and by the first power switch module (THAZ1～THAZn), the second power switch module (THAF1～THAFn), the 3rd power switch module (THBZ1～THBZn), the 4th power switch module (THBF1～THBFn), the 5th power switch module (THCZ1～THCZn), the 6th power switch module (the three-phase brachium pontis that THCF1～THCFn) forms, circuit breaker (DL1) directly inserts three phase mains, insert inlet wire reactor (L1), then be connected with the three-phase brachium pontis that the power switch module constitutes thereafter; A phase and B that the A of first three-phase isolation switch (G1) is in the three-phase bridge arm mutually go up between the brachium pontis mutually, and B phase and C that B is in the three-phase bridge arm mutually go up between the brachium pontis mutually, and C links to each other with the cathode output end of three-phase brachium pontis; The A brachium pontis parallel connection mutually of the A of second three-phase isolation switch (G2) and three-phase bridge, the B brachium pontis parallel connection mutually of B and three-phase bridge, the C brachium pontis parallel connection mutually of C and three-phase bridge; A phase and B that the A of the 3rd three-phase isolation switch (G3) is in the three-phase bridge arm mutually descend between the brachium pontis mutually, and B phase and C that B is in the three-phase bridge arm mutually descend between the brachium pontis mutually, and C links to each other with the cathode output end of three-phase brachium pontis; The negative pole of brachium pontis links to each other under the 4th three-phase isolation switch (G4) and the three-phase bridge, connects three-phase compensation capacitor (C1) thereafter again, the other end three-phase short circuit of three-phase compensation capacitor (C1); The C of first three-phase isolation switch (G1) links to each other with dc flat-wave reactor (L2), the other end of dc flat-wave reactor (L2) links to each other with second lead-out terminal (ZO2) with first lead-out terminal (ZO1) of output cathode, the C of the 3rd three-phase isolation switch (G3) be connected first cathode output end (PO1) and second cathode output end (PO2) of output negative pole, wherein second lead-out terminal (ZO2) links to each other with positive pole by the 7th three-phase isolation switch (G7), first cathode output end (PO1) links to each other with negative pole by the 8th three-phase isolation switch (G8), link to each other by the 5th three-phase isolation switch (G5) between first lead-out terminal (ZO1) and first cathode output end (PO1), link to each other by the 6th three-phase isolation switch (G6) between second lead-out terminal (ZO2) and second cathode output end (PO2); Positive pole has two lead-out terminals during ice-melt: first lead-out terminal (ZO1) and second lead-out terminal (ZO2), negative pole has two lead-out terminals: first cathode output end (PO1) and second cathode output end (PO2), wherein second lead-out terminal (ZO2) links to each other with positive pole by the 7th three-phase isolation switch (G7), first cathode output end (PO1) links to each other with negative pole by the 8th three-phase isolation switch (G8), link to each other by the 5th three-phase isolation switch (G5) between first lead-out terminal (ZO1) and first cathode output end (PO1), link to each other by the 6th three-phase isolation switch (G6) between second lead-out terminal (ZO2) and second cathode output end (PO2); A, B, C three-phase line are connected to respectively: first lead-out terminal (ZO1), second lead-out terminal (ZO2) and first cathode output end (PO1), (G5～break-make G8) need to select each phase circuit of ice-melt by the 5th～the 8th three-phase isolation switch.

2. reusable according to claim 1 is the DC de-icing device of TSC, it is characterized in that: single power switch module is made up of grading resistor (Rp), damping resistance (Rs), damping capacitor (Cs) and thyristor (SCR), 1～15 power switch module series connection constitutes single-phase brachium pontis, grading resistor (Rp) and thyristor (SCR) static state voltage equipoise that is used in parallel, damping resistance (Rs) and damping capacitor (Cs) series connection back are in parallel with thyristor (SCR).

3. reusable according to claim 1 is the DC de-icing device of TSC, it is characterized in that: inlet wire reactor (L1) adopts air core reactor.

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