Three-core five-post type earth current automatic tracking and compensating system
Technical field
The utility model relates to a kind of three-core five-post type earth current automatic tracking and compensating system; can be used as a kind of from motion tracking arc suppression coil compensation system access power distribution network; flow through during in order to the compensation power distribution network generation single-phase earthing earthing capacitance current of earth point; reduce earth point fault current elimination ground connection arc light, protection distribution net equipment thereby play.Belong to the electric equipment technical field,
Background technology
Domestic at present common from motion tracking arc suppression coil compensation system, generally include grounding transformer, controlled arc suppression coil, auxiliary adjustment part and controller part.For example: the Chinese patent communique discloses a kind of utility application, its name is called " automatic tracking and compensating arc distinction device ", number of patent application is " application number 91107531.3 ", its design feature is made up of grounding transformer, arc-suppression reactor and control system, and control system is formed by connecting by earth resistance, phase shifter, current rectifying and wave filtering circuit, single-shot trigger circuit and execution loop etc.The operation principle of this utility model is: under the artificial residual voltage source effect that produces, arc-suppression reactor and the resistance that is connected in series, and three-phase ground capacitance produces series resonance, the control system basis is to series resonant tank residual voltage and zero-sequence current bit comparison mutually, adjust the inductance value of reactor, thereby realize compensation effect.This utility model has following shortcoming: (1) because grounding transformer and controlled arc suppression coil are high voltage electric equipment, and are two independent parts of making, therefore cause complete bucking-out system take up an area of big, cost is high.(2) because control system is made of discrete circuit, and therefore, electric original paper is many, circuit structure is complicated, performance is unreliable.
The utility model content
The utility model technical issues that need to address, i.e. the purpose of this utility model is in order to overcome existing, shortcoming that circuit structure complicated big from motion tracking arc suppression coil compensation system bulk, and a kind of three-core five-post type earth current automatic tracking and compensating system is provided.
Technical problem of the present utility model can adopt following technical scheme to solve: three-core five-post type earth current automatic tracking and compensating system, and its design feature is: comprise three core five-pole transformers, controlled inductance current generator, current detecting unit and controller; Three phase windings of three core five-pole transformers are respectively on three iron core column, every phase winding comprises a winding and several secondary winding, winding inserts A, B, the C three-phase of electrical network major loop, and secondary winding connects into after the open-delta connection to be connected with the inductance current generator or to connect into to provide to stand after the indentation connection uses AC power; The control input end of inductance current generator connects the output of controller; Current detecting unit is arranged on a winding earth end of transformer, and its signal output part connects the detection signal input of controller.
By transformer principle as can be known, three phase windings of three core five-pole transformers respectively on three iron core column, the zero sequence flux circuit of the transformer of flowing through when two iron core column are used to provide system generation single-phase earthing in addition.When the distribution three-phase voltage is symmetrical fully, each low pressure secondary winding open delta end (Lm of three core five-pole transformers, therefore Nm) voltage approaches 0V, that is the voltage that is applied on each inductance current generator is very little, and three core five-pole transformers winding A, a B, C phase current are very little.Behind power distribution network generation single-phase earthing, because the imbalance of three phase-to-ground voltages, cause each secondary winding end (Lm, Nm) produce residual voltage, the height of its terminal voltage is different with the difference of impedance ground, therefore obtain voltage on the inductance current generator 3, control by control section 5 can make each inductance current generator produce inductance current I1, I2, ... .In, and each secondary inductance current phase place is basic identical, according to the transformer flux compensation principle, therefore three core five-pole transformers 2 once each phase winding electric current be IA=IB=IC=(I1*W1+I2*W2+....+In*Wn)/W0, the size of electric current is identical with phase place, the inductance current of the earth fault of therefore flowing through is IL=IA+IB+IC=3* (I1*W1+I2*W2+....+In*Wn)/W0.Because the inductance current of each inductance current generator can be regulated arbitrarily between 0A to In ampere; therefore regulate by 5 pairs of inductance current generators of control section group 3; the size of circuit capacitive earth current numerical value before can making IL numerical value near distribution generation single-phase earthing; the controlled zero sequence inductance current and the line mutual-ground capacitor electric current that are produced by three core five-pole transformers are offseted; thereby significantly reduce the ground connection residual flow, thereby reach the purpose of eliminating ground connection arc light protection distribution net equipment.
By the size of system control cpu to a zero sequence inductance current of control powerstat of inductance current generator, the big I of a zero sequence inductance current detects by current detecting unit and control section and accurately regulates.
Technical problem of the present utility model also can solve by taking following measure:
Described three core five-pole transformers are every to be made of a high pressure winding and n low pressure winding, n=1~100, the a of each low pressure winding, b, c three-phase are according to the end to end formation open delta connection of the identical winding of the number of turn, open delta end Lm, Nm connect corresponding controlled inductance current generator m, n=1~100 wherein, m=1~n.
Described three core five-pole transformers are every to be made of a high pressure winding and n low pressure winding, n=1~100, and a of one of them low pressure winding, b, c three-phase are made of the indentation connection provides station AC distribution power supply.
Described controlled inductance current generator is made up of N group controlled inductance load branch, n=1~100, each group controlled inductance load branch is by reactor Xm (m=1,2, ... .N) and gate-controlled switch Km (m=1,2 ... .N) constitute, gate-controlled switch Km is made of controllable silicon SCR, IGBT, GTO, IGCT or vacuum switch.
Each branch road reactor Xm (m=1,2 ... numerical value .N) can or take other to distribute pattern by geometric ratio, equivalent distribution.
Described current detecting unit is conventional high-voltage current detector, and it helps control section to detect adjustable inductance current output Io, accurately controls the output inductance current for control section foundation is provided.
Described controller is made of single-chip microcomputer and electronic power switch conducting control loop, the input of described single-chip microcomputer connects the signal output part of current detecting unit, the input that signal output part connects electronic power switch conducting control loop, and the output of electronic power switch conducting control loop connects the control end of controlled inductance current generator; Or adopt pulse transformer coupling pattern commonly used to carry out electrical isolation, pulse transformer output extremely links to each other with electronic power switch control and carries out switch control.
Also comprise harmonic filter, described harmonic filter is formed by inductance, capacitances in series.
The beneficial effects of the utility model are:
1, adjustable range is wide, and minimum rising transfers electric current can reach 0A, and can transfer to specified inductance current continuously, stepless difference during adjusting, evenly linear regulation.
2, owing to adopt the electronic power switch power device, open with the turn-off time and be the microsecond level, so governing speed is exceedingly fast.
3, owing to abandoned two kinds of modes that high-tension apparatus is interconnected that tradition adopts grounding transformer extraction system neutral point and arc suppression coil to regulate inductance current from the motion tracking arc suppression coil, be aided with low pressure inductance current control appliance again and replace three-core five-post type transformer formation residual voltage, can significantly reduce floor space (reaching 30%) and be lowered into the cover system cost.
4, the three-core five-post type transformer is a conventional design, does not have any special process process, and integrated system does not exist any mechanically actuated operation and control section when adopting electronic power switch, so the reliability height, and operation maintenance is simple.
Description of drawings
Fig. 1 is a circuit structure block diagram of the present utility model.
Fig. 2 is the electrical schematic diagram of the utility model embodiment 1.
Fig. 3 is the inductance current generator electrical schematic diagram of one of them embodiment of the utility model.
Fig. 4 is the electrical schematic diagram of the filter circuit of the utility model embodiment.
Fig. 5 is the electrical schematic diagram of the controller of the utility model embodiment.
Embodiment
Below in conjunction with drawings and Examples the utility model is described in detail.
Fig. 1, Fig. 2 and Fig. 5 constitute embodiment 1 of the present utility model.
As can be seen from Figure 1, present embodiment comprises that three core five-pole transformers 2, n organize controlled inductance current generator 3 (n span 1~100, down together), current detecting unit 4, control section 5 and harmonic filter circuit 6, three core five-pole transformers 2 insert distribution network system bus A, B, C three-phase by three-phase breaker 1.Three core five-pole transformers 2 are every to be made of a high pressure winding and n low pressure winding, the a of each low pressure winding, b, c three-phase are according to the end to end formation open delta connection of the identical winding of the number of turn, open delta end Lm and Nm connect corresponding controlled inductance current generator, n=1~100 wherein, m=1~n.
As can be seen from Figure 2, the specific implementation principle of inductance current generator 3 each unit is as follows in the utility model: form (N span 1~100, down together) by N group controlled inductance load branch.Each group controlled inductance load branch by reactor Xm (m=1,2 ... .N) and gate-controlled switch Km (m=1,2 ... .N) constitute, each branch road reactor Xm (m=1,2 ... numerical value .N) can be by geometric ratio, equivalently distribute or take other to distribute pattern.Gate-controlled switch Km can be made of controllable silicon SCR, IGBT, GTO, IGCT or vacuum switch etc.For each branch road, when the conducting state that changes the switch that reactor was connected in series, just can change the electric current output of this branch road, as adopt controlled electronic power switch, then this branch current can be 0 to Uk/Xm (m=1,2 ... quick adjustment arbitrarily .n), because every branch current is quick adjustment continuously all, thus total current I1=(I ' 1+I ' 2+...+I ' n) just can realize according to the conducting state of inductance current of required transformer by suitable each switch of control.General control mode can be according to the complete turning part of required primary current switch, and keeps one of them to be in conducting angle scalable state, can reduce the harmonic content of primary circuit like this.
With the electric pressure is that 10kV, specified output inductance current are that 80A is an example, and the implementation method of the utility model embodiment 1 is described:
As shown in Figure 1 and Figure 2, three core five-pole transformer high-pressure sides are K=W0/W1=36.4 with low-pressure side umber of turn ratio in the present embodiment, and the every phase rated current in high-pressure side is 26.7 amperes, so the low-pressure side electric current is the I1=970 ampere.The inductance current generator of design is made of 3 branch roads, gets every branch road maximum current and equates i.e. I ' 1=I ' 2=I ' 3=324 ampere, so reactor X1=X2=X3=1.54 ohm.
When a required zero sequence total current scope is 0~26.7A, can only regulate the conducting angle of one of them electronic power switch such as K1, when a required zero sequence total current scope is 26.7A~53.4A, one of them switch of conducting such as K1 and the conducting angle of only regulating a switch such as K2 fully, as a required zero sequence total current scope wherein two switches such as K1, K2 of conducting fully when being 53.4A~80A, and the conducting adjustable angle of maintained switch K3 only.Even do not take any filtering measures in this case, 3 subharmonic also can be very little.
In the present embodiment, electronic power switch conducting control loop, its output extremely links to each other by coupling of employing photoelectricity and electronic power switch control and controls.
Provided by the utility model from motion tracking arc suppression coil compensation system, only need a three-core five-post type arc suppression transformer, be equipped with suitable low voltage control part, just can constitute a controlled arc-extinguishing system that cover Current Regulation scope is extremely wide, governing speed is fast.
Fig. 1, Fig. 3, Fig. 4 and Fig. 5 can constitute embodiment 2 of the present utility model.
Less or when higher, can insert harmonic filter 6 in the position as shown when way as shown in Figure 3 at a certain branch road to harmonic requirement.As shown in Figure 4, harmonic filter 6 is made of common inductance, capacity cell polyphone.As shown in Figure 5, described controller 5 is made of single-chip microcomputer and electronic power switch conducting control loop, the input of described single-chip microcomputer connects the signal output part of current detecting unit 4, the input that signal output part connects electronic power switch conducting control loop, and the output of electronic power switch conducting control loop connects the control end of controlled inductance current generator 3; Or adopt pulse transformer coupling pattern commonly used to carry out electrical isolation, pulse transformer output extremely links to each other with electronic power switch control and carries out switch control.
The characteristics of other embodiment of the utility model are: described three core five-pole transformers 2 are every to be made of a high pressure winding and n low pressure winding, described three core five-pole transformers 2 are every to be made of a high pressure winding and n low pressure winding, n=1~100, a of one of them low pressure winding, b, c three-phase are made of the indentation connection provides station AC distribution power supply.Gate-controlled switch Km is made of controllable silicon or controllable silicon and vacuum switch, wherein m=1~n.All the other are with embodiment 1 or embodiment 2.