CN208753997U

CN208753997U - A kind of three-phase load unbalance self-checking device

Info

Publication number: CN208753997U
Application number: CN201821448150.9U
Authority: CN
Inventors: 郑元昌; 张良杨; 王丽娟; 季苹; 向云松
Original assignee: SHANGHAI FATO ENTERPRISE GROUP CO Ltd
Current assignee: SHANGHAI FATO ENTERPRISE GROUP CO Ltd
Priority date: 2018-09-05
Filing date: 2018-09-05
Publication date: 2019-04-16
Anticipated expiration: 2028-09-05

Abstract

The utility model provides a kind of three-phase load unbalance self-checking device; it includes cabinet body; it is characterized in that; the front side of cabinet body is equipped with cabinet door, and cabinet door and cabinet body lateral margin are hinged, and rain-proof top cover is equipped at the top of cabinet body; the side on cabinet body top is equipped with wire connecting terminal of transformer; the other side on cabinet body top is equipped with breaker, and the lower section of breaker is equipped with Surge Protector, and cabinet body lower part is equipped with control module；Utility model has the advantages that being made of SPC module, breaker of plastic casing, wire connecting terminal of transformer and Surge Protector; it is fixed in cabinet body; it is sequentially connected by busbar or other conducting wires; filter circuit unit, APF sampling, SPC, APF master control, drive circuit unit, APF mainboard is arranged in SPC module; the power quality problems such as reactive power, harmonic current, the threephase load balanced loss occurred in operation of power networks are effectively administered, safety, the reliability and stability of operation of power networks are improved.

Description

A kind of three-phase load unbalance self-checking device

Technical field

The utility model relates to electrical energy transportation field more particularly to a kind of three-phase load unbalance self-checking devices.

Background technique

In the city dweller and rural power grids power supply system of low voltage three-phase four-wire system: since electricity consumer is mostly single-phase load or list It is mutually mixed with three-phase load, and the difference of payload difference and electricity consumption time.So three alternate imbalance electricity in power grid Stream is objective reality, and this electricity consumption unbalance condition irregularities, can not also be predicted in advance.Result in low-voltage power supply system The secular disequilibrium of system threephase load.For three phase unbalance current, power department in addition to as far as possible reasonably distribution load it Outside almost without what effective solution.

Out-of-balance current in power grid will increase the copper loss of route and transformer, also will increase the iron loss of transformer, reduce The power output of transformer even will affect the safe operation of transformer, will ultimately result in the imbalance of three-phase voltage.

Utility model content

The purpose of the utility model is to provide a kind of three-phase load unbalance self-checking devices.

To achieve the goals above, the technical solution of the utility model is:

A kind of three-phase load unbalance self-checking device, it includes cabinet body, which is characterized in that is set on front side of the cabinet body There is a cabinet door, the lateral margin of the cabinet door and cabinet body is hinged, and the cabinet body and cabinet door are stainless steel material, the top of the cabinet body Equipped with rain-proof top cover, the side on the cabinet body top is equipped with wire connecting terminal of transformer, and the other side on the cabinet body top is equipped with disconnected Road device, the output end of the wire connecting terminal of transformer and the input terminal of breaker are electrically connected, and the lower section of the breaker is equipped with Surge Protector, the output end of the breaker and the input terminal of Surge Protector are electrically connected, and the lower part of the cabinet body is equipped with Control module,

The control module includes power module, sampling module, main control module, drive module, filter module, three-phase correction Module and dc-link capacitance module, the output end of the wire connecting terminal of transformer and the input terminal of sampling module are electrically connected, The power module and sampling module, three-phase rectification module and main control module are electrically connected, the output end of the Surge Protector It is electrically connected with the input terminal of filter module,

The input of the wire connecting terminal of transformer terminates three-phase input, the sampling module include three voltage transformers and Three current transformers, the output end of the wire connecting terminal of transformer are respectively connected to three voltage transformers and three Current Mutual Inductances The input terminal of device, the output end of the voltage transformer connect one end of first resistor and second resistance, the first resistor respectively The first operational amplifier of another termination inverting input terminal, another termination second operational amplifier of the second resistance it is anti- Phase input terminal, the other end of the second resistance are also grounded by 3rd resistor, the anti-phase input of first operational amplifier End is connect with one end of the 4th resistance and the 5th resistance, and the other end of the 4th resistance and one end of first capacitor connect, institute The other end for stating first capacitor is connect with the output end of the first operational amplifier, and the output end of first operational amplifier passes through The output end of second capacity earth, first operational amplifier is connect with one end of the 6th resistance, the 6th resistance it is another The connection of the normal phase input end of one end and second operational amplifier, the inverting input terminal and the second operation of the second operational amplifier The output end of amplifier connects, and the output end of the second operational amplifier makees the output of voltage transformer,

The output end of the current transformer connects one end of the 7th resistance and the 8th resistance respectively, the 7th resistance it is another The other end of one end of one end and third capacitor and the 5th capacitor, the 8th resistance is connect with one end of the 4th capacitor, described The other end of third capacitor and the 4th capacitor is grounded, and the other end of the 8th resistance also connects with the other end of the 5th capacitor Connect, one end of the 5th capacitor is connect with the normal phase input end of third operational amplifier, the other end of the 5th capacitor with The inverting input terminal of third operational amplifier connects, and the output end of the third operational amplifier and one end of the 9th resistance connect Connect, the other end of the 9th resistance by the 8th capacity earth, the bias voltage input of the third operational amplifier with One end of tenth resistance connects, and the other end of the tenth resistance passes through the 7th capacity earth, the 9th resistance and the tenth electricity The other end of resistance makees the both-end output of current transformer.

Utility model has the advantages that three-phase imbalance controlling device is connect by SPC module, breaker of plastic casing, mutual inductor Line terminals and Surge Protector composition, are installed in stainless steel cabinet body with fixing piece, are sequentially connected by busbar or other conducting wires, Filter circuit unit, APF sampling, SPC, APF master control, drive circuit unit, APF mainboard is arranged in SPC module, effectively improvement power grid The power quality problems such as reactive power, harmonic current, the threephase load balanced loss of emerged in operation, improve operation of power networks Safety, reliability and stability；Using voltage transformer, the sampling of current transformer and A/D conversion circuit, through DSP operation, IGBT inversion generates the compensation electric current an of three-phase imbalance, feeds back to power grid, can effectively realize three-phase load unbalance automatically Dynamic control, stablize each phase voltage normal.

Detailed description of the invention

Fig. 1 is the concrete structure schematic diagram of the utility model；

Fig. 2 is the internal framework schematic diagram of the utility model；

Fig. 3 is the structural schematic diagram of voltage transformer in the utility model；

Fig. 4 is the structural schematic diagram of current transformer in the utility model；

Fig. 5 is the structural schematic diagram of the first acquisition chip and the second acquisition chip in the utility model；

Fig. 6 is the structural schematic diagram of third acquisition chip in the utility model；

Fig. 7 is the structural schematic diagram of master controller in the utility model；

Fig. 8 is the structural schematic diagram of the first transceiving chip, the second transceiving chip and third transceiving chip in the utility model；

Fig. 9 is the structural schematic diagram (third ~ the 6th driving of the first driving chip and the second driving chip in the utility model Chip omits)；

Figure 10 is the structural schematic diagram of power supply module in the utility model.

Appended drawing reference:

1 cabinet body, 2 cabinet door, 3 rain-proof top cover, 4 wire connecting terminal of transformer, 5 breaker, 6 Surge Protector

7 control module, 71 power supply module, 72 sampling module, 73 main control module

74 drive module, 75 filter module, 76 three-phase rectification module, 77 dc-link capacitance

8 three-phase input, 81 A phase, which inputs 82 B phases and inputs 83 C phases, inputs 84 zero curves

T1 voltage transformer T2 current transformer

U1 the first operational amplifier U2 second operational amplifier U3 third operational amplifier

U4 the first acquisition chip U5 the second acquisition chip U6 third acquisition chip

U7 microcontroller U8 the first transceiving chip U9 the second transceiving chip U10 third transceiving chip

The 4th driving chip of U11 the first driving chip U12 the second driving chip U13 third driving chip U14

The 6th driving chip of the 5th driving chip U16 of U15.

Specific embodiment

The technical solution of the utility model is clearly and completely described below in conjunction with attached drawing, it is clear that described Embodiment is the utility model a part of the embodiment, instead of all the embodiments.Based on the embodiments of the present invention, originally Field those of ordinary skill every other embodiment obtained without making creative work belongs to practical Novel protected range.

The utility model discloses a kind of three-phase load unbalance self-checking devices, it includes cabinet body 1, and feature exists In as shown in Figure 1, the front side of the cabinet body 1 is equipped with a cabinet door 2, the cabinet door 2 and the lateral margin of cabinet body 1 are hinged, the cabinet body 1 It is stainless steel material with cabinet door 2, the top of the cabinet body 1 is equipped with rain-proof top cover 3, and the side on 1 top of cabinet body is equipped with mutual Sensor connecting terminal 4, the other side on 1 top of cabinet body are equipped with breaker 5, the output end of the wire connecting terminal of transformer 4 with The input terminal of breaker 5 is electrically connected, and the lower section of the breaker 5 is equipped with Surge Protector 6, the output end of the breaker 5 It is electrically connected with the input terminal of Surge Protector 6, the lower part of the cabinet body 1 is equipped with control module 7, as shown in Fig. 2, the control Module 7 includes power module 71, sampling module 72, main control module 73, drive module 74, filter module 75, three-phase rectification module 76 and 77 module of dc-link capacitance, the output end of the wire connecting terminal of transformer 4 electrically connect with the input terminal of sampling module 72 It connects, the power module 71 is electrically connected with sampling module 72, three-phase rectification module 76 and main control module 73, the surge protection The output end of device 6 and the input terminal of filter module 75 are electrically connected, when the interference in electric loop because of the external world generates point suddenly When peak current or voltage, breaker 5 cuts off circuit in time, and shunting can be connected in Surge Protector 6 in a very short period of time, from And avoid damage of the surge to other equipment in circuit.

The sampling module 72 include voltage transformer T1 and current transformer T2, the wire connecting terminal of transformer 4 it is defeated Enter to terminate three-phase input 8, the output end of the wire connecting terminal of transformer 4 is respectively connected to three voltage transformer T1 and three electric currents The input terminal of mutual inductor T2, as shown in figure 3, the output end of voltage transformer T1 connects first resistor R1's and second resistance R2 respectively One end, the inverting input terminal of the first operational amplifier of another termination U1 of the first resistor R1, the second resistance R2's is another The inverting input terminal of one termination second operational amplifier U2, the other end of the second resistance R2 also pass through 3rd resistor R3 and connect The inverting input terminal on ground, the first operational amplifier U1 is connect with one end of the 4th resistance R4 and the 5th resistance R5, and described The other end of four resistance R4 is connect with one end of first capacitor C1, the other end and the first operational amplifier of the first capacitor C1 The output end of U1 connects, and the output end of the first operational amplifier U1 is grounded by the second capacitor C2, and first operation is put Big device U1, first resistor R1, second resistance R2 and the 4th resistance R4 form differential amplifier, the 5th resistance R5 cooperation first Capacitor C1 filtering, keeps temperature change, mains fluctuations and this kind of common-mode signal of external interference defeated when voltage mutually samples Very little out.

As shown in figure 3, the output end of the first operational amplifier U1 is connect with one end of the 6th resistance R6, the described 6th The other end of resistance R6 is connect with the normal phase input end of second operational amplifier U2, and the reverse phase of the second operational amplifier U2 is defeated Enter end to connect with the output end of second operational amplifier U2, the output end of the second operational amplifier U2 makees voltage transformer T1 Output, second operational amplifier U2 is as voltage follower, and input impedance is high, and output impedance is low, plays buffering, isolation, improves The effect of load capacity.

As shown in figure 4, the output end of current transformer T2 connects one end of the 7th resistance R7 and the 8th resistance R8 respectively, it is described The other end of 7th resistance R7 and one end of third capacitor C3 and the 5th capacitor C5, the other end and the 4th of the 8th resistance R8 One end of capacitor C4 connects, and the other end of the third capacitor C3 and the 4th capacitor C4 are grounded, and the 8th resistance R8's is another One end is also connect with the other end of the 5th capacitor C5, and the 7th resistance R7 and third capacitor C3 constitute the input of the one end current transformer T2 RC low-pass filtering, the 8th resistance R8 and the 4th capacitor C4 constitute the RC low-pass filtering of current transformer T2 other end input.

One end of the 5th capacitor C5 is connect with the normal phase input end of third operational amplifier U3, the 5th capacitor C5 The other end connect with the inverting input terminal of third operational amplifier U3 ,+the 5V of third operational amplifier U3 input passes through the 6th Capacitor C6 ground connection, the output end of the third operational amplifier U3 are connect with one end of the 9th resistance R9, the 9th resistance R9 The other end pass through the 8th capacitor C8 be grounded, the bias voltage input and the tenth resistance R10 of the third operational amplifier U3 One end connection, the other end of the tenth resistance R10 passes through the 7th capacitor C7 ground connection, the 9th resistance R9 and the tenth resistance The other end of R10 makees the both-end output of current transformer T2, and third operational amplifier U3 is used as comparator, for detecting electricity The size relation of current transformer T2 double-width grinding exports high level, otherwise exports low if homophase input is greater than anti-phase input Level.

When it is implemented, as shown in Figure 1, the three-phase input 8 includes that A phase inputs 81, B phase and inputs 82, C phase and inputs 83 and Zero curve 84, the filter module 75 include the 9th capacitor C9, the tenth capacitor C10, the 11st capacitor C11, the first inductance L1, second Inductance L2 and third inductance L3, the A phase input 81 and pass sequentially through wire connecting terminal of transformer 4, breaker 5 and Surge Protector 6 It is connected to one end of the 9th capacitor C9 and one end of the first inductance L1, B phase inputs 82 and passes sequentially through wire connecting terminal of transformer 4, open circuit Device 5 and Surge Protector 6 are connected to one end of the tenth capacitor C10 and one end of the second inductance L2, and C phase inputs 83 and passes sequentially through mutual inductance Device connecting terminal 4, breaker 5 and Surge Protector 6 are connected to one end of the 11st capacitor C11 and one end of third inductance L3, institute State another terminal connecting zero line 84 of the 9th capacitor C9, the tenth capacitor C10, the 11st capacitor C11.

Three-phase rectification module 76 includes the first IGBTQ1, the 2nd IGBTQ2, the 3rd IGBTQ3, the 4th IGBTQ4, the 5th IGBTQ5 and the 6th IGBTQ6, the collection of the other end of the first inductance L1 and the emitter of the first IGBTQ1 and the 4th IGBTQ4 Electrode connection, the other end of the second inductance L2 connect with the collector of the emitter of the 2nd IGBTQ2 and the 5th IGBTQ5, The other end of the third inductance L3 is connect with the collector of the emitter of the 3rd IGBTQ3 and the 6th IGBTQ6.

77 module of dc-link capacitance include the 12nd capacitor C12 and the 13rd capacitor C13, described first The collector of IGBTQ1, the 2nd IGBTQ2 and the 3rd IGBTQ3 are connect with one end of the 12nd capacitor C12, and the described 4th The emitter of IGBTQ4, the 5th IGBTQ5 and the 6th IGBTQ6 are connect with one end of the 13rd capacitor C13, the 12nd electricity The other end for holding C12 and the 13rd capacitor C13 is connect with zero curve 84.

The main control module 73 includes the first acquisition chip U4, the second acquisition chip U5, third acquisition chip U6 and micro-control Device U7 processed, as shown in Figure 5 and Figure 6, the first acquisition chip U4, the second acquisition chip U5 and third acquisition chip U6 are used AD7606, as shown in fig. 7, the microcontroller U7 uses STM32F407ZET6, the output end of the voltage transformer T1 is distinguished 61,59,57 3 voltage input feet of the first acquisition chip U4 are connect, the both-end output end of the current transformer T2 connects respectively 49,51,53,57,59,61 feet of three acquisition chip U6, the first acquisition chip U4, the second acquisition chip U5 and third acquisition chip 16,17,18,19,20,21,22,24,25,27,28,29,30,31,32, the 33 feet one-to-one correspondence of U6 connects microcontroller U7's FSMC, i.e., 85,86,114,115,58,59,60,63,64,65,66,67,68,77,78,79 feet, microcontroller U7 pass through these FSMC pin carries out static storage for the sample information of three-phase voltage and electric current.

As shown in figure 8, main control module 73 includes the first transceiving chip U8, the second transceiving chip U9 and third transceiving chip U10, the first transceiving chip U8, the second transceiving chip U9 and third transceiving chip U10 use LVC245A, the microcontroller These USART(universal synchronous of 96,10,141,97,11, the 140 of device U7/asynchronous serial reception/transmitter) pin one-to-one correspondence It is connected to 2,3,4,5,6, the 7 of the first transceiving chip U8 these input pins, 98,12,139,99,13, the 136 of microcontroller U7 These USART feet connect one to one to 2,3,4,5,6, the 7 of the second transceiving chip U9 these input pins, microcontroller U7's 100,14,135,103,15,134 these USART feet connect one to one to third transceiving chip U10 2,3,4,5,6,7 this A little input pins.

As shown in figure 9, the drive module 74 includes the first driving chip U11, the second driving chip U12, third driving Chip U13, the 4th driving chip U14, the 5th driving chip U15 and the 6th driving chip U16, third driving chip U13, the 4th The structure of driving chip U14, the 5th driving chip U15 and the 6th driving chip U16 and the first driving chip U11, the second driving Chip U12 is consistent, is omitted in Fig. 9, and the first ~ the 6th driving chip U16 uses HCPL-316J, the first transceiving chip U8 18,17,16 feet connect 1,5,6 feet of the first driving chip U11 respectively, 15,14,13 feet of the first transceiving chip U8 connect respectively 1,5,6 feet of two driving chip U12,18,17,16 feet of the second transceiving chip U9 connect 1,5, the 6 of third driving chip U13 respectively Foot, 15,14,13 feet of the second transceiving chip U9 connect 1,5,6 feet of the 4th driving chip U14 respectively, third transceiving chip U10's 18,17,16 feet connect 1,5,6 feet of the 5th driving chip U15 respectively, and 15,14,13 feet of third transceiving chip U10 connect respectively 1,5,6 feet of six driving chip U16.

14 feet of first ~ the 6th driving chip U16 are connected with each other, and 13,12 feet of the first ~ the 6th driving chip U16 connect+ 10,9 feet of 15V voltage, the first ~ the 6th driving chip U11 ~ 16 connect -9V voltage, and 15V voltage is connected to NMOS tube drain electrode, NMOS Pipe source electrode and PMOS tube drain electrode are connected to output end, and -9V voltage is connected to PMOS tube source electrode, the first ~ the 6th driving chip U11 ~ 16 11 feet are input to the grid of NMOS tube and PMOS tube, and NOMS and PMOS tube constitute two-way switch, and NOMS pipe is made charging and opened It closes, and PMOS tube consumes the electric energy of driving chip when no component connects, and eliminates the influence of body diode, prevents to leakage Electricity.

The three-phase rectification module 76 includes the first IGBTQ1, the 2nd IGBTQ2, the 3rd IGBTQ3, the 4th IGBTQ4, the In five IGBTQ5 and the 6th IGBTQ6, the first ~ the 6th driving chip U16, NMOS tube source electrode and PMOS tube drain electrode and the first ~ the 6th The base stage of IGBTQ6 connects one to one.

The specific work step of the three-phase rectification module 76 works normally lower power grid input referring to state of the art The three-phase current at end is I, and A, B, C threephase load end electric current are IA, IB, IC, and IA+IB+IC=3I；When IA be greater than I, IB=I, IC is less than I, and microcontroller U7 is according to the offset △ IA of A phase load electric current, and the 6th IGBTQ6 of control is connected and deadline, is Dc-link capacitance module 77 charges, until the IA '=I at A phase load end；Then microcontroller U7 is further according to C phase load current terminal The offset △ IC of electric current, controls the on and off time of the 2nd IGBTQ2, and the dc-link capacitance module 77 is discharged to C Phase load end, until C phase load end electric current IC '=I；Other situations are similarly.

Control module 7, i.e. SPC module carry out the rotation of dq coordinate according to system power, extract the imbalance point of positive sequence negative phase-sequence Amount, three-phase issue the electric current with unbalanced component opposite in phase equal in magnitude, can be by three-phase by uneven part compensation to zero Out-of-balance current is corrected into three-phase equilibrium electric current.It, can 100% school no matter active three-phase imbalance or idle three-phase imbalance Just arrive complete equipilibrium.

SPC generates the fundamental wave of capacitive or perception by six IGBT power inverter Q1 ~ 6 according to the reactive power of system Electric current realizes that the purpose of dynamic passive compensation, compensation target value can be set by operation panel, is not in overcompensation, and And compensation is smooth, will not generate the impact of shoving to load and power grid.

Finally, it should be noted that the above various embodiments is only to illustrate the technical solution of the utility model, rather than it is limited System；Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should Understand: it is still possible to modify the technical solutions described in the foregoing embodiments, or to some or all of Technical characteristic is equivalently replaced；And these are modified or replaceed, it does not separate the essence of the corresponding technical solution, and this is practical new The range of each embodiment technical solution of type.

Claims

1. a kind of three-phase load unbalance self-checking device, it includes cabinet body, which is characterized in that the front side of the cabinet body is equipped with The lateral margin of one cabinet door, the cabinet door and cabinet body is hinged, and the cabinet body and cabinet door are stainless steel material, sets at the top of the cabinet body There is rain-proof top cover, the side on the cabinet body top is equipped with wire connecting terminal of transformer, and the other side on the cabinet body top is equipped with open circuit Device, the output end of the wire connecting terminal of transformer and the input terminal of breaker are electrically connected, and the lower section of the breaker is equipped with wave Surge protector, the output end of the breaker and the input terminal of Surge Protector are electrically connected, and the lower part of the cabinet body is equipped with control Molding block,

The control module includes power module, sampling module, main control module, drive module, filter module, three-phase rectification module With dc-link capacitance module, the output end of the wire connecting terminal of transformer and the input terminal of sampling module are electrically connected, described Power module and sampling module, three-phase rectification module and main control module are electrically connected, the output end of the Surge Protector and filter The input terminal of wave module is electrically connected,

The input of the wire connecting terminal of transformer terminates three-phase input, and the sampling module includes three voltage transformers and three Current transformer, the output end of the wire connecting terminal of transformer are respectively connected to three voltage transformers and three current transformers Input terminal, the output end of the voltage transformer connect one end of first resistor and second resistance respectively, the first resistor it is another The inverting input terminal of one the first operational amplifier of termination, the reverse phase of another termination second operational amplifier of the second resistance are defeated Enter end, the other end of the second resistance also by 3rd resistor be grounded, the inverting input terminal of first operational amplifier with One end of the connection of one end of 4th resistance and the 5th resistance, the other end of the 4th resistance and first capacitor connects, and described the The other end of one capacitor is connect with the output end of the first operational amplifier, and the output end of first operational amplifier passes through second The output end of capacity earth, first operational amplifier is connect with one end of the 6th resistance, the other end of the 6th resistance It is connect with the normal phase input end of second operational amplifier, the inverting input terminal of the second operational amplifier and the second operation amplifier The output end of device connects, and the output end of the second operational amplifier makees the output of voltage transformer,

The output end of the current transformer connects one end of the 7th resistance and the 8th resistance, the other end of the 7th resistance respectively It is connect with the other end of one end of third capacitor and the 5th capacitor, the 8th resistance with one end of the 4th capacitor, the third The other end of capacitor and the 4th capacitor is grounded, and the other end of the 8th resistance is also connect with the other end of the 5th capacitor, institute The one end for stating the 5th capacitor is connect with the normal phase input end of third operational amplifier, and the other end and third of the 5th capacitor are transported The inverting input terminal connection of amplifier is calculated, the output end of the third operational amplifier is connect with one end of the 9th resistance, described The other end of 9th resistance passes through the 8th capacity earth, the bias voltage input and the tenth resistance of the third operational amplifier One end connection, the other end of the tenth resistance by the 7th capacity earth, the 9th resistance and the tenth resistance it is another Make the both-end output of current transformer in end.

2. a kind of three-phase load unbalance self-checking device according to claim 1, which is characterized in that the three-phase is defeated Enter inputted including A phase, B phase inputs, C phase inputs and zero curve, the filter module include the 9th capacitor, the tenth capacitor, the 11st Capacitor, the first inductance, the second inductance and third inductance, the A phase, which inputs, passes sequentially through wire connecting terminal of transformer, breaker and wave Surge protector is connected to one end of the 9th capacitor and one end of the first inductance, and B phase, which inputs, passes sequentially through wire connecting terminal of transformer, open circuit Device and Surge Protector are connected to one end of the tenth capacitor and one end of the second inductance, and C phase, which inputs, passes sequentially through mutual inductor interstar connection end Son, breaker and Surge Protector are connected to one end of the 11st capacitor and one end of third inductance, the 9th capacitor, the tenth electricity Hold, another terminal connecting zero line of the 11st capacitor.

3. a kind of three-phase load unbalance self-checking device according to claim 2, which is characterized in that three-phase corrects mould Block include the first IGBT, the 2nd IGBT, the 3rd IGBT, the 4th IGBT, the 5th IGBT and the 6th IGBT, first inductance it is another One end is connect with the collector of the emitter of the first IGBT and the 4th IGBT, the other end of second inductance and the 2nd IGBT's The collector of emitter and the 5th IGBT connection, the other end of the third inductance and the 3rd IGBT emitter and the 6th IGBT Collector connection.