CN201323457Y - A high-accuracy collecting-distributing automatic reactive power compensation control system - Google Patents

Abstract

The utility model discloses a high-precision collecting and distributing automatic reactive power compensation control system, which is characterized in that: the three-phase main busbars A, B and C of the power grid are connected to the incoming line end of the circuit breaker QF, and the outgoing line ends of the circuit breaker are respectively connected in parallel Each single-phase fuse in the arrester F1, arrester F2, arrester F3 and primary main circuit; each single-phase fuse is connected to the main contact of each phase contactor, and the other end of the contactor main contact is connected to the contactor of each phase. Thermal relays, capacitors, discharge lamps and reactors are connected; the other ends of the fuses of the secondary control loops are respectively connected to the intelligent distribution controllers; each controller samples the voltage and current signals on the single-phase circuit respectively, and uses Three independent collection and distribution intelligent compensation circuits drive the contactor action, select the combination of compensation capacitors, and realize the proportional compensation switching on each single-phase circuit, so that the dispersion compensation accuracy is higher, and the intelligent distribution between phases Complementary and non-interfering, realize dynamic three-phase balance.

Description

A High-Precision Distributed Automatic Reactive Power Compensation Control System

Technical field:

The utility model relates to the technical field of reactive power compensation for power distribution system grids, in particular to a high-precision collection and distribution automatic reactive power compensation control system.

Background technique:

With the rapid development of the national economy and the increase of daily electricity consumption, the economic operation of the power grid has been paid more and more attention. Especially in some civil buildings, a large number of single-phase loads are used, such as lighting and air conditioning. Due to the randomness of load changes, it is easy to cause unbalanced three-phase load power supply, especially in residential buildings. It is more serious, and the resulting harm will cause the heating of the rotating electrical machine, resulting in the misoperation of various protection systems with negative sequence components as the starting components, and at the same time shorten the service life of many electrical equipment, all of which cause the electric energy of the grid The many hidden dangers brought about by the decline in quality have not yet received enough attention from everyone.

In the past, the sampling signal of the three-phase co-complement adjustment and compensation reactive power is taken from any one of the three phases, which will cause the other two phases that are not detected to be either over-compensated or under-compensated. In addition, the three-phase co-compensation compensation capacitor usually uses a three-phase symmetrical delta connection, and the three-phase load connected to the power transformer is asymmetrical. When the total power factor of the three phases after compensation is equal to 1, there will also be Some are undercompensated and some are overcompensated.

If it is under-compensated, the voltage at the receiving end is lower than the voltage at the transmitting end, the loop current of the compensation phase will increase, and the main loop equipment such as lines and circuit breakers will be burned out due to the increase in current.

If it is overcompensation, the voltage at the receiving terminal is higher than the voltage at the transmitting terminal, the voltage of the overcompensated phase will increase, causing some "virtual voltage" of the system to appear, which may cause some control and protection components and other electrical equipment to be damaged due to overcompensation. Voltage consumption and damage; Considering the line voltage loss, the voltage of the power transmitting terminal is generally 5% to 10% higher than the rated voltage; in the case of overcompensation, coupled with the voltage increase, the voltage of the power receiving terminal exceeds the rated voltage The value is far greater than 10%. If the capacitor is connected in parallel to the secondary side of the transformer, the impedance of the transformer should also be included in the impedance of the line, so the voltage at the receiving end will increase even more. The increase of operating voltage will have a very adverse effect on the safe operation of power capacitors and the entire system. In addition, the three-phase asymmetrical load is compensated by a three-phase symmetrical delta-connected power capacitor bank, so the capacity of the transformer cannot be fully utilized.

Therefore, in the case of serious three-phase unbalance, using the traditional three-phase reactive power compensation method will not only save energy, but will waste resources, and it is difficult to effectively compensate the reactive power compensation of the system. Disadvantages such as lack of compensation and undercompensation are even more harmful to the normal operation of the entire power grid.

Invention content:

Aiming at the deficiency of ordinary reactive power compensation in the background technology, the utility model designs a high-precision centralized and distributed automatic reactive power compensation control system, and adopts three-phase independent sub-compensation measures, thereby completely changing the traditional reactive power parameter signal. Sampling method, through the independent single-phase intelligent sub-compensation controller to sample the voltage and current signals on each single-phase circuit, and track the reactive power change on each single-phase in the system, and control the reactive power of each phase Physical quantity, with the power factor of each phase set by the user as the switching reference limit, according to the size of the inductive load of each phase and the level of the actual single-phase power factor, three independent distributed intelligent compensation circuits are used to reasonably select the compensation capacitor. The combination performs decentralized precise automatic reactive power compensation for each single phase, the compensation effect is very obvious, and there will be no mutual interference and pre-emptive switching compensation for other phases, completely avoiding the occurrence of under-compensation and over-compensation. Since the single-phase star-connected capacitor bank is used on the circuit, the capacitors of each phase are put into the power grid according to the principle of "taking level and making up", realizing the proportional distribution and compensation switching technology on each single-phase circuit, and improving the static compensation accuracy of the system .

The technical solution adopted by the utility model to solve the technical problem is: a high-precision distributed automatic reactive power compensation control system, which is mainly composed of circuit breakers, transformers, controllers, fuses, contactor thermal relays, discharge lamps, and capacitors. It is composed of a reactor; it is characterized in that: A, B, and C phases of the three-phase four-wire power lines of the main busbars A, B, C, and N of the power grid are connected to the incoming line end of the circuit breaker QF, and the outgoing line ends A, The three phases B and C are respectively connected with arrester F1, arrester F2, arrester F3, fast-acting fuse (FUa1～FUan), fuse (FUb1～FUbn), fuse (FUc1～FUcn) of the primary main circuit and secondary control One end of the protection fuse FU1, protection fuse FU2 and protection fuse FU3 of the circuit is connected.

The other ends of the fast fuses (FUa1～FUan), fuses (FUb1～FUbn) and fuses (FUc1～FUcn) of the primary main circuit described in the utility model are respectively connected to switching contactors (KMa1～KMan) via wires , the contactor (KMb1～KMBn), the main contact of the contactor (KMc1～KMcn), the other end of the main contact of the contactor is respectively connected to each phase thermal relay (1KH1～1KHn), thermal relay (2KH1～2KHn), thermal relay (2KH1～2KHn), thermal relay Relay (3KH1 ~ 3KHn); the other end of the thermal relay is connected in parallel with the discharge lamp (LDa1 ~ LDan), discharge lamp (LDb1 ~ LDbn), discharge lamp (LDc1 ~ LDcn) of each branch circuit and the compensation capacitor in star connection (Ca1～Can), compensation capacitor (Cb1～Cbn), compensation capacitor (Cc1～Ccn), the other end of the capacitor is connected with reactor (La1～Lan), reactor (Lb1～Lbn), reactor (Lc1～Lcn) , the common end of the star is well grounded.

The secondary control loop of the utility model is taken from the C-phase power supply, and is respectively connected with the output passive contacts of the controller A, controller B, and controller C, and the other end of the passive contact output of each controller is connected to the Thermal relay (1KH1～1KHn), thermal relay (2KH1～2KHn), thermal relay (3KH1～3KHn) are connected with auxiliary contacts, and the other end of auxiliary contact is connected with switching contactor coil (KMa1～KMan), contactor Coils (KMb1~KMbn), contactor coils (KMc1~KMcn), and the other ends of the contactor coils of each phase are respectively connected to the N line of the power supply in parallel.

In the voltage detection loop described in the utility model, the other ends of the fuse FU1, fuse FU2, and fuse FU3 of the secondary control loop are respectively connected to the phase voltage detection units of the three phases A, B, and C in the controller to control The ground terminals of the phase voltage detection units of devices A, B, and C are respectively connected in parallel to the N wire of the three-phase four-wire.

In the current detection circuit described in the utility model, the current transformer CT1, the current transformer CT2, the current transformer CT3 connected in series of the main circuit three-phase power supply A phase, B phase and C phase, the secondary current transformer The S1 and S2 ends of the line are respectively connected to the single-phase current detection unit in the intelligent single-phase compensation controller A, controller B, and controller C, and the secondary line of the S2 end of each transformer is short-circuited and grounded;

All N wires in the circuit described in the utility model are connected to the N wires of the power supply.

The beneficial effect of the technology of the utility model is: a high-precision distributed automatic reactive power compensation control system, which is not only suitable for the three-phase unbalanced reactive power compensation of the lines of large-scale factories and mines, and transformers, but also suitable for specific users such as shopping malls The reactive power compensation of asymmetrical loads such as electric energy in office buildings and residential areas has the characteristics of high real-time performance, high precision and super energy saving, so it has broad application prospects.

This utility model new technology can not only improve the power factor of the entire circuit of the system, save energy and reduce loss, improve voltage quality, save electricity, increase the active capacity of the transformer, etc., but also can fully tap the working capacity of the equipment, reduce the line The loss rate is 20%, improving the starting and operating conditions of electrical equipment, and increasing the power supply capacity of the line.

Description of drawings:

Below in conjunction with accompanying drawing, the utility model is further described:

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

In Figure 1, 1, current transformer CT1, 2, main circuit breaker QF, 3, fast fuse (FUa1), 4, protective fuse (FU1), 5, switching contactor (KMa1), 6, Thermal relay protector 1KH1, 7, compensation capacitor (Ca1), 8, reactor (La1), 9, discharge lamp (LDa1), 10, intelligent single-phase compensation main controller A, 11, arrester (F1). 12. Voltage signal detection point.

Detailed ways:

In the embodiment of Fig. 1, a high-precision distributed automatic reactive power compensation control system, now taking the A-phase precise compensation circuit as an example, emphatically describes the implementation process of the utility model: power grid main busbars A, B, C, Phase A in the three-phase four-wire power supply of N is connected to the incoming line terminal of circuit breaker 2 (QF), and the outgoing line terminal of circuit breaker 2 uses wires for phase A to connect with arrester 11 (arrestor F1) and fast fuse 3 of the primary main circuit respectively. (FUa1) and the protective fuse 4 (FU1) of the secondary control circuit are connected in parallel.

The other end of the fuse 3 (FUa1) of the primary main circuit described in the utility model is respectively connected to the main contact of the switching contactor 5 (KMa1) through the wire, and the outlet terminal of the contactor main contact 5 is connected to the thermal relay 6 (1KH1 ); the other end of the thermal relay 6 is respectively connected in parallel with the A-phase compensation capacitor 7 (Ca1) and the discharge lamp 9 (LDa1) of the branch circuit, and the other end of the A-phase compensation capacitor 7 is connected with the reactor 8 (La1), and its star connection The common terminal of the law should be well grounded.

The other end of the protective fuse 4 (FU1) of the secondary control loop described in the utility model is respectively connected to the phase voltage detection unit of the A phase in the controller 10, and the ground terminal of the A phase voltage detection unit of the controller 10 is connected to The N line of the three-phase four-wire power supply.

In the main circuit described in the utility model, the A phase of the three-phase power supply is connected in series with a current transformer 1 (CT1), and the secondary lines S1 and S2 of the transformer 1 are connected to the A of the intelligent single-phase compensation main controller 10. A single-phase current detection unit in the phase, and the secondary line of the S2 end of the current transformer 1 is short-circuited and grounded;

The secondary control loop power supply described in the utility model is taken from the C phase on the main bus three-phase four-line, and supplies the passive contact of the output of the intelligent single-phase compensation main controller 10, and the passive contact output of the main controller 10 is connected with the thermal The normally closed auxiliary contact of the relay 6 (1KH1) is connected; the other end of the normally closed auxiliary contact of the thermal relay 6 is connected with the switching contactor 5 coil (KMa1), and the other end of the switching contactor 5 coil is connected to the power supply N line.

All the N wires described in the utility model are all drawn from the N wires of the power supply.

The working principle of the circuit of the utility model is: connect the circuit breaker of the main circuit, the A-phase electricity in the three-phase power supply passes through the fuse (FUa1～FUan) of the main circuit→switching and cutting the main contact of the contactor (KMa1～KMan)→ Thermal relay (1KH1～1KHn)→compensation capacitor (Ca1～Can) in star connection and then respectively connected to branch circuit discharge lamp (LDa1～LDan) and reactor (La1～Lan)→grounding.

The input signal of the intelligent sub-compensation controller of phase A is sampled from the current signal provided by the current transformer of phase A and the single-phase voltage signal introduced through the fuse (FU1), which is automatically processed by the controller so that the reactive power of each phase becomes the main Control quantity, voltage and power factor as optional auxiliary control quantity (different from simple power factor or voltage), and then perform multiple filtering to calculate the reactive power change of the A-phase branch circuit, using single-phase independent collection and distribution Intelligent compensation circuit, rationally select the combination of A-phase compensation capacitors (Ca1~Can), determine the number of opening and closing of A-phase compensation switching contactors (KMa1~KMan), drive the switching contactors (KMa1~KMan) action, contactor (KMa1～KMan) After the contacts are closed, the number of A-phase switching compensation capacitors (Ca1～Can) and A-phase reactors (La1-Lan) is connected to achieve the purpose of reactive power compensation for the A-phase circuit. (La1~Lan) as an option, if there is a need for filtering, then decide to connect in series.

The protection of phase A circuit is carried out by fast-fusing fuse (FUa1～Fuan) and thermal relay protector (1KH1～1KHn). If the main circuit has overcurrent, the fuse will blow quickly (FUa1～FUan) Main circuit; if the main circuit is overheated, the thermal relay protector (1KH1～1KHn) disconnects the secondary control circuit of the switching contactor (KMa1～KMan), and cuts off the power through the switching contactor (KMa1～KMan), Its main contact disconnects the primary main circuit, thereby realizing the protection of the A-phase circuit.

The power-off protection of the compensation capacitors (Ca1~Can) of phase A is realized by discharging with the discharge lamps (LDa1~Ldan) in each branch circuit, and can prolong the service life of the compensation capacitors.

The component structure and circuit working principle of phase B and phase C are exactly the same as those of phase A, so we will not repeat them one by one.

The overload protection and overvoltage protection of the main circuit of the precise compensation system are carried out by the main circuit breaker QF and lightning arresters (F1 ~ F3).

Claims (5)

1, a kind of high-precision collecting and distributing type auto-reactive compensation control system mainly is made of circuit breaker, instrument transformer, controller, fuse, contactor, thermal relay, discharge lamp, capacitor and reactor; It is characterized in that: A, B, C three end of incoming cables of circuit breaker Q F that joins in the three-phase and four-line of electrical network main bus bar A, B, C, N, the leading-out terminal of the A of circuit breaker Q F, B, C three-phase link with protection fuse protection fuse FU1, the protection fuse FU2 of fast acting fuse FUa1～FUan, fuse FUb1～FUbn, fuse FUc1～FUcn and the secondary control loop of lightning arrester F1, lightning arrester F2, lightning arrester F3, a major loop, the end of protection fuse FU3 respectively.

2, a kind of high-precision collecting and distributing type auto-reactive compensation control system according to claim 1, it is characterized in that: the other end of the fast acting fuse FUa1～FUan of a major loop, fuse FUb1～FUbn, fuse FUc1～FUcn meets cut-in and cut-off contactor KMa1～KMan, contactor KMb1～KMbn, the contactor KMc1～KMcn main contact of each phase respectively with lead, and the main contact other end of each contactor meets the thermal relay 1KH1～1KHn of each phase, thermal relay 2KH1～2KHn, thermal relay 3KH1～3KHn respectively; Discharge lamp LDa1～LDan, discharge lamp LDb1～LDbn, discharge lamp LDc1～LDcn and each compensation condenser Ca1～Can, compensation condenser Cb1～Cbn, compensation condenser Cc1～Ccn mutually of the duplexure of the other end of thermal relay each phase respectively in parallel, reactor La1～the Lan of another each phase of termination of capacitor, reactor Lb1～Lbn, reactor Lc1～Lcn, the common end grounding of its wye connection.

3, a kind of high-precision collecting and distributing type auto-reactive compensation control system according to claim 1, it is characterized in that: the secondary control loop power supply is taken from the C phase of main bus bar three-phase and four-line, and be connected in parallel to each single-phase compensation master controller A respectively, controller B, the output of controller C does not have source contact, the no source contact of each controller output is connected in series the thermal relay 1KH1～1KHn to each single-phase loop again, thermal relay 2KH1～2KHn, the auxiliary contact of thermal relay 3KH1～3KHn, the other end serial connection of thermal relay auxiliary contact is to the cut-in and cut-off contactor coil KMa1～KMan in each single-phase loop, contactor coil KMb1～KMbn, contactor coil KMc1～KMcn, the other end of each phase loop contactor coil are respectively and be connected to the N line of power supply; All N lines all are connected on the N line of power supply in the circuit.

4, a kind of high-precision collecting and distributing type auto-reactive compensation control system according to claim 1, it is characterized in that: the fuse FU1 of voltage detecting loop and secondary control loop, fuse FU2, fuse FU3 link, the other end connects A, the B in the controller, the phase voltage detecting unit of C three-phase respectively, and the phase voltage detecting unit earth terminal of controller A, B, C respectively and be connected on the N line of three-phase four-wire power.

5, a kind of high-precision collecting and distributing type auto-reactive compensation control system according to claim 1, it is characterized in that: current detection circuit, take from current transformer CT1, current transformer CT2, current transformer CT3 that major loop three phase mains A phase, B phase and C are connected in series mutually, secondary line S1, the S2 of current transformer end connects monophase current detecting unit among three the single-phase compensation master controller of intelligence A, controller B, the controller C respectively, and will every secondary line short circuit and ground connection that instrument transformer S2 holds.

Images