CN201038752Y - Variable tuning capacitor type automatic compensation arc-suppression coil - Google Patents

Abstract

The utility model provides an automatic compensating arc suppression coil with variable displacement, which belongs to the technical field of arc suppression of power distribution system. The arc suppression coil adopts the microcontroller technology to collect the current and voltage of the system neutral point and other data at different states and calculate the system parameters such as capacitance and current and then judge whether to input the capacitor unit. The first winding of the arc suppression coil is taken as the main inductance, while the second winding is carried with the capacitance load and changes the equivalent inductance by changing the size of the capacitance load through the controller. The capacitor unit at the second side of the arc suppression coil adopts the subdivided multiunit capacitors, while the tap position is divided into 15 with a wide adjusting scope. In addition, the zero passage switching form of the vacuum contactor is adopted so that the response speed can reach the millisecond level. If compared with the prior art, the utility model can accurately calculate the capacitance and current, make a rapid response and accurately control the compensation.

Description

Capacitance-adjustable automatic compensating arc extinguishing coil

(1) technical field

The utility model relates to a kind of arc-extinction device that is applied to power distribution network, specifically a kind of capacitance-adjustable automatic compensating arc extinguishing coil that can accurately calculate capacitance current, response fast, accurate control compensation.

(2) technical background

At present, the most frequently used compensation arrangement has three kinds:

1. regulate tapped: the tap that utilizes on load tap changer to come stepping to switch the ground connection arc suppression coil, to measure and transfer sense, its operation principle adopts the displacement voltage method.

2. regulate excitation-type: on the mixed lateral column core of the both sides of grounding transformer three-limb core, be wound with the excitation winding of upper and lower band tap, constitute the arc suppression coil of adjustable excited formula.When the generation single-phase earthing, utilize the control thyristor angle of flow to regulate arc suppression coil, the size of Control current, thus reach the magnetic saturation program that changes the both sides column iron core, the capacity of smooth adjustment arc suppression coil and automatic compensation single-phase-to-ground current.

3. regulate GAP TYPE: the arc suppression coil iron core is divided into moving iron core and static iron core two parts.Moving iron core is driven through mechanical driving device by motor, can upper and lowerly regulate, and changes the air gap of two iron cores, realizes the continuous stepless adjustment of inductance, makes offset current adjustable continuously.

But above-mentioned three kinds of compensation arrangements exist all that response speed is slow, the compensation defective that accuracy is not high and adjustable range is narrow.

(3) summary of the invention

Technical assignment of the present utility model is slow at prior art compensation arrangement response speed, the compensation accuracy is not high, the deficiency that adjustable range is narrow, provide a kind of not only response speed fast, adjustable range is wide, and can accurately calculate capacitance current, the capacitance-adjustable automatic compensating arc extinguishing coil of accurate control compensation.

The technical scheme that its technical problem that solves the utility model adopts is:

This capacitance-adjustable automatic compensating arc extinguishing coil adopts with mode, the running status of the automatic detection of grid of system, when electrical network normally moved, real-time tracking calculated the humorous degree that takes off of power-to-ground capacitance electric current and electrical network, the control switch circuit makes arc suppression coil be operated in position away from resonance point; When electrical network generation single phase ground fault, adjust the reactance value of arc suppression coil rapidly, make electrical network take off humorous degree and approach 0, residual flow reduces to about 1A.

Adopt the microcontroller technology can accurately calculate capacitance current, accurately control compensation.System gathers data such as the system neutral electric current, voltage of different conditions as required, calculates the capacitance current system parameters, judges whether to drop into the capacitor group then.

Switching capacitance formula arc suppression coil is based on the principle of single-phase transformer, utilizes the adjustment of inductance method of equiva lent impedance.A winding is as main inductance, and secondary winding has capacitive load, and the size by the load of controller control capacitance changes its equivalent inductance value.

The multiple unit capacitor of the capacitor group employing capacity segmentation of arc suppression coil secondary side, nearly 15 grades of gears, the precision height of adjusting; When capacitor all drops into, the electric current minimum of arc suppression coil compensation, the electric current maximum of compensation when capacitor all withdraws from, adjustable range is wide.Adopt vacuum contactor operating passing zero mode, response speed is fast, can reach Millisecond.

Capacitance-adjustable automatic compensating arc extinguishing coil of the present utility model compared with prior art, the beneficial effect that is produced is: response speed is fast, adjustable range is wide, and can accurately calculate capacitance current, accurately control compensation.

(4) description of drawings

Equivalent electric circuit when accompanying drawing 1 is system's generation single phase ground fault;

Accompanying drawing 2 is arc suppression coil overall structure figure;

Accompanying drawing 3 is adjustable capacitive-based arc-suppression coil schematic diagrams;

Accompanying drawing 4 is controller hardware block diagrams.

Among the figure, C ₀Be single-phase direct-to-ground capacitance, U _NBe neutral point voltage, I _LBe coil current, I _DCBe earthing capacitance current; JDB is a grounding transformer, and PT1, PT2 are voltage transformer, and GLD is an isolation switch, and BLQ is a lightning arrester, and XHXQ is an arc suppression coil, and KZP is a control flow, and KZQ is a controller, and CT is a current transformer; C1, C2, C3, C4 are ground capacity, T1, T2, T3, T4 are vacuum contactor, and L1 is a winding, and L2 is a secondary winding.

(5) embodiment

Explain below below in conjunction with accompanying drawing 1-4 capacitance-adjustable automatic compensating arc extinguishing coil of the present utility model being done.

As shown in Figure 1, when single-phase (as the A phase) ground connection takes place in system, neutral point voltage U _NTo be elevated to phase voltage by zero, so will flow through electric current I in the arc suppression coil _L, its expression formula $I_L=\frac{U_N}{\mathrm{\ωL}}=\frac{U_X}{\mathrm{\ωL}}$ (U _xScalar for the phase voltage size).Its direction flows back to system by the fault point, than neutral point voltage U _NQuadrature lagging is promptly than A leading 90 degree of just often phase voltage mutually; And flow back to the earthing capacitance current I of system by the fault point this moment _DCA phase phase voltage quadrature lagging during than normal operation.So, flow back to the inductive current I of the arc suppression coil of system by the fault point _LWith earthing capacitance current I _DCDirection just the opposite.If suitably select the size of arc suppression coil inductance L, make $\mathrm{\ωL}=\frac{1}{3\mathrm{\ω}{C}_0}$ , then $I_L=\frac{U_X}{\mathrm{\ωL}}=3\mathrm{\ω}{C}_0{U}_X$ , the electric current by the fault point will equal zero so, i.e. earthing capacitance current I _DCAll by the inductive current I of arc suppression coil, compensate, thereby ground arc is extinguished automatically.

As shown in Figure 2, whole system is made up of grounding transformer JDB, arc suppression coil XHXQ, controller KZQ etc.Grounding transformer JDB is used for the isolated neutral system that neutral point is not drawn, for neutral point is drawn by system; Arc suppression coil XHXQ body is the iron-core inductance coil of a band secondary winding, and inductance current is provided; P voltage transformer T1, PT2, current transformer CT provide signal for control; Lightning arrester BLQ protection arc suppression coil XHXQ; Control flow KZP is the major part of adjustable capacitive-based arc-suppression coil, and empty frame partly is controller KZQ among the figure, and it comprises automatic compensating controller, capacitor, noncontacting switch assembly etc.

As shown in Figure 3, the winding L 1 of arc suppression coil XHXQ does not have tap, manufactures and designs simpler.Adopt vacuum contactor T1, T2, T3, the mode of T4 operating passing zero capacitor group, response speed is fast, can reach Millisecond, and the capacitor group adopts four groups of parallel connections, is respectively ground capacity C1, C2, C3, nearly 15 grades of C4, gear, adjustable range is wide.

As shown in Figure 4, voltage transitions, analog filtering (ALF), automatic range tracking, multipath conversion (MPX) and analog-to-digital conversion (A/D) constitute signal acquisition module, gather three phase-to-ground voltages, neutral point voltage and the electric current of electrical network, discern single phase ground fault, series resonance state according to three phase-to-ground voltages and neutral point voltage, to carry out control corresponding.CPU is the core of TT﹠C system, the signal of gathering is handled control vacuum contactor T1, T2, T3, the switching of T4, the demonstration of display screen etc.

Claims (2)

1. capacitance-adjustable automatic compensating arc extinguishing coil, it is characterized in that, a winding of arc suppression coil is as main inductance, secondary winding connects capacitive load, change the equivalent inductance value of arc suppression coil by the size of controller control capacitance load, because the direction of the inductive current of arc suppression coil and earthing capacitance current is opposite, all or part of inductive current by arc suppression coil of earthing capacitance current compensates, thereby ground arc is extinguished automatically or weakens.

2. arc suppression coil according to claim 1 is characterized in that, the neutral point that arc suppression coil and connected controller get access to grid by grounding transformer.

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