CN102130462A - Intelligent compensation device for unbalanced electricity load - Google Patents

Abstract

The invention discloses an intelligent electrical load unbalance compensation device, which belongs to the technical field of low voltage power distribution networks. The intelligent electrical load unbalance compensation device comprises a central control device, and a current and voltage sampling device, a zero sequence compensation device and a negative sequence compensation device which are in control connection with the central control device, wherein the current and voltage sampling device is used for collecting current and voltage signals of a load circuit; the zero sequence compensation device consists of a zigzag transformer TR and an impedance dynamic regulation device; and the negative sequence compensation device consists of combination switches FK1 to FK3, and grouped-switched compensation capacitors of each phase. The device can filter zero sequence current to be within 1A in a rated unbalanced load, increase the unbalance of three phases of current to be within 10 percent, ensure high electric energy utilization rate, safe and reliable running and remarkable energy saving effects, reduce loss and cost and improve the economic efficiency. The whole device is connected into a power grid in parallel, and is convenient to arrange, simple to use and applied to the low voltage power distribution networks of industrial mining, enterprises, traffic transportation department, residential areas and the like.

Description

Intelligent compensation device for unbalanced electricity load

technical field

The invention belongs to the technical field of electric low-voltage distribution network, in particular to an intelligent compensation device for unbalanced electric load.

Background technique

In the traditional three-phase four-wire distribution transformer wiring system in my country, due to various reasons such as the low-voltage single-phase load cannot be fully divided manually, the actual operating rate of the distributed load is different, and the unbalanced three-phase load is unavoidable. of. And this unbalanced three-phase load will inevitably lead to increased loss, decreased power efficiency, increased zero-sequence current, and shortened service life of equipment.

Harm to the transformer: The unbalanced three-phase load will make the transformer run asymmetrically, which will increase the loss of the transformer. According to the transformer operating regulations, the neutral current of the transformer in operation cannot exceed 25% of the rated current of the low-voltage side of the transformer. In addition, the unbalanced three-phase load will cause excessive zero-sequence current of the transformer, increase the temperature of some metal parts, and even cause the transformer to burn out.

Neutral line and neutral point voltage problems: The zero-sequence current of the neutral line is too large, causing the neutral line to burn out, causing problems such as excessive neutral point voltage offset.

Harm to electrical equipment: The unbalanced three-phase voltage will increase the reverse torque in the motor, which will cause the motor to heat up, the efficiency will decrease, and the energy consumption will increase. Therefore, the imbalance of three-phase voltage will shorten the service life of electrical equipment, accelerate the replacement frequency of equipment parts, and increase equipment maintenance costs.

At present, the phase-separated reactive power compensation device with the best compensation effect on the market can compensate the load, but it can only compensate for the reactive current part in the system, but it is powerless for the asymmetrical active current part. The current imbalance may be even greater, so the power supply department of the electric industry can only adjust the load by manual branching.

It can be seen from the above that the three-phase unbalance of the power system has very serious harm and influence on transformers, electrical equipment and power systems, and especially constitutes a great obstacle to the full and effective use of electric energy. In today's shortage of power supply, it is an urgent task to solve the three-phase unbalance problem of the power system.

The current AC power system is generally three-phase A, B, and C, and the positive sequence, negative sequence, and zero sequence components of the power system are determined according to the order of the three phases A, B, and C. Positive sequence: Phase A leads phase B by 120 degrees, phase B leads phase C by 120 degrees, and phase C leads phase A by 120 degrees. Negative sequence: Phase A is 120 degrees behind phase B, phase B is 120 degrees behind phase C, and phase C is 120 degrees behind phase A. Zero sequence: ABC three-phase phase is the same, which phase is neither leading nor lagging behind. The appearance of positive sequence, negative sequence and zero sequence is to analyze the asymmetry of the system voltage and current, and decompose the asymmetrical components of the three phases into symmetrical components (positive and negative sequences) and zero sequence components in the same direction. As long as it is a three-phase system, the above three components can be decomposed. For an ideal power system, due to the three-phase symmetry, the values of the negative sequence and zero sequence components are both zero (this is why we often say that there are only positive sequence components in the normal state). To make the three-phase balance, it is necessary to try to filter out the negative sequence and zero sequence components existing in the power grid. This is the theoretical basis for designing an intelligent compensation device for unbalanced electric load.

Contents of the invention

In view of the above-mentioned problems existing in the prior art, the purpose of the present invention is to design and provide a technical solution of an intelligent compensation device for unbalanced electric load, which can effectively improve the power loss and equipment damage caused by the three-phase load being unable to be evenly divided, effectively Suppress the zero-sequence current and negative-sequence current in the power grid, achieve the purpose of energy saving and emission reduction, and effectively save energy loss.

The intelligent compensation device for unbalanced electric load is characterized in that it includes a central control device and a current and voltage sampling device, a zero-sequence compensation device, and a negative-sequence compensation device connected to the control device, and the current and voltage sampling device is used to collect the current of the load circuit , voltage signal, the zero-sequence compensation device is made up of zigzag transformer TR and impedance dynamic adjustment device, and the negative-sequence compensation device is composed of composite switch FK1 and AB phase group switching compensation capacitor, composite switch FK2 and BC phase group switching Compensation capacitor, compound switch FK3 and CA phase group switching compensation capacitor.

The intelligent compensation device for unbalanced electric load is characterized in that the AB phase group switching compensation capacitors, BC phase group switching compensation capacitors, and CA phase group switching compensation capacitors are all composed of a group of parallel AC capacitors , the compensation capacitor bank adopts delta connection.

The intelligent compensation device for unbalanced electric load is characterized in that the meandering transformer TR is a three-phase winding transformer with the same number of turns of primary and secondary windings, Ia _1-2 A phase advance, Ia _1-1 connected to Ib _2-1 , Ia _2-1 connects Ic _1-1 , Ia _2-2 connects Ic _2-2 , _Ib1-1 connects Ic _2-1 , Ib _1-2 B-phase advances, Ib _2-2 connects Ic _2-2 ,, Ic _1-2 C phase advances, Ic _2-2 connects N neutral line.

The intelligent compensation device for unbalanced electric load is characterized in that the impedance dynamic adjustment device is composed of an AC contactor KM2 and a reactor L1 connected in parallel on the circuit.

The intelligent compensation device for unbalanced electric load is characterized in that it also includes a main power switch K1 and a neutral switch K2 connected to the circuit, and the neutral switch K2 is controlled and connected to the central control device.

The intelligent compensation device for unbalanced electricity load is characterized in that it also includes a lightning protection device MOV connected to the circuit, and the lightning protection device MOV is connected to the central control device under control.

The intelligent compensation device for unbalanced electricity load is characterized in that it also includes a phase loss protector QX and a main contactor KM1 connected to the circuit, and the phase loss protector QX and the main contactor KM1 are controlled and connected to the central control device.

The intelligent compensation device for unbalanced electric load is characterized in that it also includes a distribution transformer monitoring terminal connected to the central control device.

The intelligent compensation device for unbalanced electric load is characterized in that it also includes a cabinet, the central control device, the negative sequence compensation device, and the zero sequence compensation device are installed in the cabinet), and a temperature sensor and a cooling fan are arranged on the top of the cabinet. The temperature sensor and the cooling fan are controlled and connected with the central control device.

The intelligent compensation device for unbalanced electric load is characterized in that the current and voltage sampling devices are current transformers CT respectively arranged on phase A, phase B, phase C and the neutral line N1 for current signal collection. _1-5 , set voltage transformers PT _6-8 on phase A, phase B, and phase C for voltage signal acquisition.

The above-mentioned intelligent compensation device for unbalanced electric load can filter the zero-sequence current within 1A within the rated unbalanced load, increase the unbalanced degree of three-phase current to within 10%, increase the utilization rate of electric energy, reduce loss, and improve Economic benefits, cost reduction, safe and reliable operation, remarkable energy-saving effect. The whole device is connected in parallel to the low-voltage power grid, which is easy to install and use. This product is suitable for low-voltage distribution networks such as industrial and mining, enterprises, transportation departments, and residential areas.

Description of drawings

Fig. 1 is a system block diagram of the present invention;

Fig. 2 is a partial electrical schematic diagram of the present invention;

Fig. 3 is a schematic structural diagram of a meander transformer;

Fig. 4 is the circuit block diagram of central control device;

Fig. 5 is the cabinet structure schematic diagram of the present invention;

In the figure: 1-central control device, 101-DSP control chip, 102-communication circuit, 103-power supply circuit, 104-three-phase voltage sampling circuit, 105-three-phase current sampling circuit, 106-switch input circuit, 107- Zero sequence control output circuit, 108-negative sequence control output circuit;

2-current and voltage sampling device, 3-zero sequence compensation device, 301-impedance dynamic adjustment device, 4-negative sequence compensation device, 5-distribution transformer monitoring terminal, 6-temperature sensor, 7-cooling fan, 8-cabinet.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings of the description.

As shown in the figure, the intelligent compensation device for unbalanced electric load includes a central control device 1 , a current and voltage sampling device 2 , a zero-sequence compensation device 3 , and a negative-sequence compensation device 4 . The current and voltage sampling device 2 is a current transformer CT _1-5 respectively arranged on phase A, phase B, phase C and neutral wires N1 and N2 for current signal acquisition, and is arranged on phase A, phase B, The voltage transformer PT _6-8 used for voltage signal acquisition on phase C, and the current and voltage sampling device 2 are connected to the central control device 1 under control. The negative sequence compensation device 4 is composed of a compound switch FK1 and AB phase group switching compensation capacitors, a compound switch FK2 and BC phase group switching compensation capacitors, a compound switch FK3 and CA phase group switching compensation capacitors. The AB phase group switching compensation capacitor is composed of capacitors C1, C2, and C3 in parallel, the BC phase group switching compensation capacitor is composed of capacitors C4, C5, and C6 in parallel, and the CA phase group switching compensation capacitor is composed of capacitors C7, C8, and C9 in parallel. , the compensation capacitor bank adopts delta connection. The number and parameters of the parallel AC capacitors in the compensation capacitors of each phase can also be determined according to the size of the load. The composite switches FK1-FK3 are connected to the central control device 1 for control.

The zero-sequence compensation device 3 is composed of a meander transformer TR and an impedance dynamic adjustment device 301 , and the impedance dynamic adjustment device 301 is connected to the central control device 1 under control. The impedance dynamic adjustment device 301 is composed of an AC contactor KM2 and a reactor L1 connected in parallel on the circuit. The zigzag transformer TR is a three-phase winding transformer with the same number of turns of primary and secondary windings, Ia _1-2 A phase advance, Ia _1-1 is connected to Ib _2-1 , Ia _2-1 is connected to Ic _1-1 , Ia _2-2 is connected to Ic _2-2 , _Ib1-1 is connected to Ic _2-1 , Ib _1-2 is connected to B phase, Ib _2-2 is connected to Ic _2-2 , Ic _1-2 is connected to C phase, and Ic _2-2 is connected N zero line. The transformation ratio of the zigzag transformer TR (ZigZag transformer) is set to 1:1, that is, the number of turns of the primary and secondary windings is the same, so that the current input on the primary side is the same as the output current induced by the secondary side. From the wiring method of the meander transformer:

Ia1(t) = Ia2(t)

I _b1 (t) = I _b2 (t)

I _c1 (t) = I _c2 (t)

From the ratio relationship between primary and secondary sides

I _a2 (t) = I _b1 (t)

I _b2 (t) = I _c1 (t)

I _c2 (t) = I _a1 (t)

So it follows; I _a1 (t) = I _b1 (t) = I _c1 (t)

That is, the currents flowing into the primary side of the zigzag transformer TR have the same amplitude and phase, so the transformer is a very low impedance path for the zero-sequence current. Therefore, using this principle, the meandering transformer is connected in parallel to the system, so that the zero-sequence current can pass through the meandering transformer instead of the neutral line. The windings of each phase of the meander transformer are cross-connected to each other. By compensating the magnetic flux of the iron core, the windings of each phase form a high impedance to the positive sequence and negative sequence voltage, and form a low impedance to the zero sequence voltage. Connecting the meander transformer in parallel to the system can make the zero-sequence current pass through the meander transformer instead of the neutral line, thereby realizing zero-sequence current compensation. The compensation of negative sequence current adopts phase-splitting and group switching compensation capacitors, and the compensation capacitor bank adopts delta connection. The device can not only compensate the negative sequence current, automatically compensate the reactive power of the three-phase load, but also automatically adjust the asymmetry of the active power of the three-phase load.

The above intelligent compensation device for unbalanced electricity load is also connected to the circuit with a main power switch K1, a lightning protection device MOV, a phase loss protector QX, a main contactor KM1, a neutral switch K2, a main power switch K1, and a lightning protection device. MOV, phase loss protector QX, main contactor KM1, and neutral switch K2 are respectively connected to the central control device 1 under control. The phase loss protector QX mainly detects the overvoltage, undervoltage, phase loss and phase sequence error of the three-phase voltage. The lightning protection device MOV provides lightning protection for the device and the load side. There are two types of cabinets, indoor and outdoor. The central control device 1, the negative sequence compensation device 4, and the zero sequence compensation device 3 are installed in the cabinet body 8, and the temperature sensor 6 and the cooling fan 7 are installed on the top of the cabinet body 8, and the temperature sensor 6, the cooling fan 7 and the central control device 1 control connected, when the temperature in the entire cabinet was higher than the preset value, the cooling fan 7 automatically started working to dissipate heat to the device. The distribution transformer monitoring terminal 5 connected to the central control device 1 is also set in the cabinet body 8. The distribution transformer monitoring terminal 5 can monitor information such as transformers, equipment and power grid operation data in real time on site. Through the public network such as: GPRS/CDMA/GSM will The analysis results of the obtained data are transmitted to the main station of the power bureau remotely. It is also possible to control some electrical equipment through the remote control of the main station of the power bureau or the alarm information on site through the remote control port.

The central control device 1 is mainly composed of a DSP control chip 101, a communication circuit 102, a power supply circuit 103, a three-phase voltage sampling circuit 104, a three-phase current sampling circuit 105, a switch input circuit 106, a zero-sequence control output circuit 107, a negative The sequence control output circuit 108 is composed. Wherein, the communication circuit 102 is connected to the DSP control chip 101 serial interface for on-site and remote communication; the power supply circuit 102 provides the working power of the whole device; High-precision analog-to-digital conversion port, input three-phase voltage, current through voltage, current transformer current transformer CT _1-5 and voltage transformer PT _6-8 , after passing through the low-pass filter circuit, it is used as the ADC channel in the DSP Input part; the DSP control chip contains an ADC channel for sampling voltage and current to complete the sampling of voltage and current. Switch input circuit 106, zero-sequence control output circuit 107, and negative-sequence control output circuit 108 are connected to DSP control chip 101 to realize control output of negative-sequence and zero-sequence current, and input of various switch states and fault quantities.

Described DSP control chip 101 adopts the DSP (TMS320F2808) of TI Company, the 12-bit ADC converter that contains multiple channels inside this DSP, wherein 6 channels, are used for sampling ABC three-phase voltage and current signal, 2 channels are used for Sampling the load zero-sequence current and compensating the zero-sequence current; the three-phase voltage sampling circuit 104 is connected to three voltage transformers CT _6-8 , the three-phase current sampling circuit 105 is connected to five current transformers CT _1-5 , and the input three The phase voltages UA, UB, and UC pass through resistor dividers and three voltage transformers CT _6-8 ; the input load currents IA, IB, and IC respectively pass through five current transformers CT _1-5 , and then pass through a single-supply operational amplifier. (MV358I) and an AC signal amplifier circuit composed of precision resistors for amplification, and an anti-aliasing filter circuit composed of a single-supply operational amplifier (MV358I) for low-pass filtering, and send it to the DSP control chip 101. DSP control chip 101 has 16 analog input channels, 16 channels can simultaneously sample and convert synchronously, and obtain various required parameters, such as current and voltage effective values of each phase, power factor, and zero-sequence compensation amount through digital signal processing , Negative sequence compensation, etc. Switch input circuit 106, zero-sequence control output circuit 107, and negative-sequence control output circuit 108 are composed of integrated block (74HC14, ULN2004A), optocoupler (PS2501T), relay (APA3311), and realize the control and control of composite switches and contactors. Monitoring of the operating status of the entire system. The specific circuit structures of the communication circuit 102, the power supply circuit 103, the three-phase voltage sampling circuit 104, the three-phase current sampling circuit 105, the switching value input circuit 106, the zero-sequence control output circuit 107, and the negative-sequence control output circuit 108 are as follows: There are known techniques, which will not be repeated here. The DSP control chip 101 is used to complete the control work of the entire system, and the specific control method also belongs to the existing known technology, and will not be repeated here.

When working, turn on the main power switch K1 to power on the device, and the phase loss protector QX detects whether the three-phase voltage is normal. Close, the start indicator light is on, and the device starts to work normally. The current signal sampled by CT1-CT5 and the voltage signal sampled by CT6-CT8 are sent to DSP (TMS320F2808), and the negative sequence and zero sequence compensation are obtained after program processing, and the combined switch FK1-FK3 and impedance dynamic adjustment device 301 are controlled , Realistic automatic compensation for negative sequence and zero sequence.

The above-mentioned intelligent compensation device for unbalanced electric load has the following functions: eliminate the current on the zero line by sampling three-phase voltage, three-phase current, meandering transformer TR and impedance dynamic adjustment device 301, and realize zero-sequence compensation; Switching compensation capacitors, BC phase group switching compensation capacitors, CA phase group switching compensation capacitors to balance the current between AC, BC, and AB phases to achieve negative sequence compensation; thus to balance the load and equal operation; with the function of reactive power compensation, It can effectively filter out the zero-sequence current, and at the same time, it can also realize the compensation of negative sequence and zero sequence respectively, so as to achieve the effect of three-phase balance, and can completely replace the reactive power compensation device; eliminate the current on the zero line, and the device can sample the zero line Real-time current, zero-sequence compensation overload protection function, when the zero-sequence compensation is balanced, and the zero-sequence component is greater than the factory preset protection value, the device will stop working within 1 second; fault SMS alarm function, when any fault occurs in the device, It can be detected by the distribution transformer monitoring terminal 5, and then inform the user of the fault type by SMS; it can also collect the operation data of the transformer and the secondary side power grid of the low distribution, and upload it to the master station in time; the program self-test protection function, after the device is powered on , the program can automatically detect whether the static working point of the sampling circuit on the control circuit board in the device is normal; the double protection function of software and hardware in case of overvoltage, undervoltage and phase loss, when the grid voltage is overvoltage, undervoltage or phase loss, the device Stop working quickly to ensure the safety of the device; monitor the operation data of transformers and low-distribution secondary side grids and upload data in time; can filter out harmonic currents such as 3rd and 9th orders; reduce the zero-sequence impedance of distribution transformers; The additional iron loss of the transformer caused by the neutral line current; reduce the winding copper loss caused by three-phase unbalance; reduce the voltage offset caused by three-phase unbalance; reduce reactive current loss, improve power factor; prevent neutral The overheating of the line will cause the neutral line of the transformer to burn out, so as to ensure the safe operation of the transformer and improve the service life of the transformer.

1. Test data comparison test before and after compensation, see Table 1.

Table 1 Comparison records of data before and after compensation of products using different principles (experimental data of a certain day in a certain place)

Product efficiency analysis: Based on the analysis of a single 400kVA distribution transformer in a certain place, a three-phase unbalancer compensation device needs to be installed according to the capacity.

Line Loss Reduction:

      （三相平衡情况）

(three-phase balance)

Then the power loss of the component within 24H is

Considering the worst case, the balancing device is used for single-phase loads before installation, and the current only flows through the single-phase and neutral conductors:

After installing the balance

The line loss is reduced to one-sixth of that before unbalanced. This is the most extreme case, and the reduction in line loss is also the largest. In general, take the unbalanced rate of 20% at the end of the low-voltage main line or main branch line in the main application place of the device as an example. Specific analysis by three different situations of load:

(1) The load of one phase is heavy, the load of one phase is light, and the load of the third phase is the average load. When the unbalance rate is 20%, the line loss caused by the three-phase unbalance will increase by about 11%;

(2) One-phase load is heavy, two-phase load is light, and the line loss caused by three-phase unbalance increases by about 8%;

(3) One-phase load is light, two-phase load is heavy, and the line loss caused by three-phase unbalance increases by about 20%.

Transformer losses:

The total loss of the three-phase winding of the distribution transformer can be calculated similarly to the line loss when the three-phase unbalanced operation is performed. Take the zero-sequence resistance R ₀ =0.122Ω, zero-sequence reactance X ₀ =0.174Ω, and winding resistance R ₁ =0.00849Ω of a SJ, 315kVA, 10kV/0.4kV transformer as an example. When Ia=100A, Ib=200A, Ic=300A, the same power factor is 0.7, the total power loss of additional loss and additional copper loss is 3.65kW. Compared with the rated loss power of the transformer of 6.3kW, the loss increases by about 58%.

After adopting the intelligent compensation device for unbalanced power load of the present invention, it is expected to reduce the line loss of the low-voltage station area of the power grid to 6%, the transformer loss to 3.5%, and the comprehensive line loss to 9.5%, reducing the line loss to 4.5% and the transformer loss to 2.6%. , The comprehensive line loss is 7.1%.

The calculation is based on 8760 hours of operation per year, the load rate is 0.6, and the electricity fee is calculated at 0.6 yuan/kWh.

Energy saving = running time × load rate × rated power × comprehensive line loss reduction rate

A single transformer can save annually: Electric energy 7.50×10 ⁴ kWh

Electricity fee 45,000 RMB

The energy consumption of the device itself, according to the experimental test, the power consumption of a single intelligent compensation device for power load imbalance is less than 80W, and the annual electricity bill is 420.5 yuan.

Calculated on the basis of the average consumption of 400 grams of standard coal for every kilowatt-hour of electricity generated. Each transformer can save 30 tons of coal, 300 cubic meters of water, 21 tons of carbon dust, 75 tons of carbon dioxide, 2.25 tons of sulfur dioxide, and 1.14 tons of nitrogen oxides. The energy-saving effect is obvious.

The above is an analysis of the direct energy-saving effect after the installation of a single transformer, excluding the economic penalties imposed by power operators on users whose power factor exceeds the standard. From the above results, it can be seen that the intelligent compensation device for power load imbalance On the premise that the sum remains unchanged, the load is evenly distributed to the three-phase output. At this time, the zero-sequence current is greatly reduced, which greatly reduces the zero-sequence loss and neutral point potential offset; it is different from the reactive power compensation device on the market. Compared with it, its energy-saving effect is increased by more than 30%, the quality of power supply is improved, and the loss of power supply is reduced.

Claims (10)

1. the uneven intelligent compensation device of power load, it is characterized in that comprising that central control unit (1) reaches and the current-voltage sampling device (2) of its control connection, zero sequence compensation device (3), negative sequence compensation device (4), current-voltage sampling device (2) is used to gather the electric current of load circuit, voltage signal, described zero sequence compensation device (3) is by tortuous transformer TR, impedance dynamic adjustments device (301) is formed, and described negative sequence compensation device (4) is by combination switch FK1 and AB phase grouping switching compensation condenser, combination switch FK2 and BC phase grouping switching compensation condenser, combination switch FK3 and CA phase grouping switching compensation condenser are formed.

2. the uneven intelligent compensation device of power load as claimed in claim 1, it is characterized in that described AB phase grouping switching compensation condenser, BC phase grouping switching compensation condenser, CA phase grouping switching compensation condenser form by the ac capacitor of one group of parallel connection, this compensation condenser group adopts delta connection.

3. the uneven intelligent compensation device of power load as claimed in claim 1 is characterized in that described tortuous transformer TR is the identical three-phase winding transformer of former and deputy limit umber of turn, Ia _1-2A advances mutually, Ia _1-1Connect Ib _2-1, Ia _2-1Connect Ic _1-1, Ia _2-2Connect Ic _2-2, Ib1 _-1Connect Ic _2-1, Ib _1-2B advances mutually, Ib _2-2Connect Ic _2-2,, Ic _1-2C advances mutually, Ic _2-2Connect the N zero line.

4. the uneven intelligent compensation device of power load as claimed in claim 1 is characterized in that described impedance dynamic adjustments device (301) is made up of the A.C. contactor KM2, the reactor L1 that are connected in parallel on the circuit.

5. the uneven intelligent compensation device of power load as claimed in claim 1 is characterized in that also comprising the total power switch K1, the zero line K switch 2 that are connected on the circuit, zero line K switch 2 and central control unit (1) control connection.

6. the uneven intelligent compensation device of power load as claimed in claim 1 is characterized in that also comprising the lightning protection device MOV that is connected on the circuit, lightning protection device MOV and central control unit (1) control connection.

7. the uneven intelligent compensation device of power load as claimed in claim 1 is characterized in that also comprising the open phase protector QX, the main contactor KM1 that are connected on the circuit, open phase protector QX, main contactor KM1 and central control unit (1) control connection.

8. the uneven intelligent compensation device of power load as claimed in claim 1 is characterized in that also comprising the Distribution Transformer Terminal Unit (5) with central control unit (1) control connection.

9. the uneven intelligent compensation device of power load as claimed in claim 1, it is characterized in that also comprising cabinet (8), central control unit (1), negative sequence compensation device (4), zero sequence compensation device (3) are installed in the cabinet (8), cabinet (8) top is provided with temperature sensor (6) and radiator fan (7), temperature sensor (6) and radiator fan (7) and central control unit (1) control connection.

10.. the uneven intelligent compensation device of power load as claimed in claim 1 is characterized in that described current-voltage sampling device (2) reaches mutually and is used for the current transformer CT that current signal is gathered on the neutral line N1 for being separately positioned on A phase, B phase, C _1-5, be arranged on the voltage transformer pt that A phase, B phase, C are used for voltage signal acquisition on mutually _6-8

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