CN104617587B - SVG and SVC coordinated control method based on reactive power fluctuation frequency division - Google Patents

Abstract

The invention discloses an SVG and SVC coordinated control method based on reactive power fluctuation frequency division. The method comprises the steps of filtering reactive power compensation demand value by using low frequency reactive power component as the reference of SVC reactive power compensation and high frequency component as the reference of SVG; adjusting the cutoff frequency of a filter to enable the system powder factor and the voltage flicker value to meet relevant standards; switching to the SVC priority compensation mode without filtering by using the reactive powder demand directly as the reference of SVC and the difference between the reactive power demand and the practical output of SVC as the reference of SVG when the SVG output current exceeds the limited value; and after a certain time, switching to the frequency division compensation mode. In combination with the characteristics of slower SVC response with lower unit capacity cost and faster SVG response with larger unit capacity cost, the method disclosed by the invention can coordinately control SVC and SVG, achieves the reactive power precise compensation under certain economic requirements and reduces the voltage flicker value.

Description

A kind of svg based on reactive power fluctuation frequency partition and svc control method for coordinating

Technical field

The present invention relates to power quality controlling technical field, more particularly, to svg and svc based on reactive power fluctuation frequency partition Control method for coordinating.

Background technology

There are a large amount of load or burden without work, such as transmission line of electricity, transformer, asynchronous motor, electric arc furnaces all consume in power system Reactive power.All kinds of corrupt practices creep in for idle presence, increased the loss of circuit and equipment, occupies the capacity of circuit and equipment, Voltage drop is formed on circuit with equipment and then causes Voltage-stabilizing Problems.For reduce the idle adverse effect brought it is proposed that The principle of " layering and zoning, local compensation ", some reactive-load compensation equipments also put into operation in succession, such as traditional shnt capacitor, Synchronous capacitor, SVC (svc) etc., recently as the development of high-power electric and electronic technology, static reacance Generator (svg) starts to put into industrial applications.

Reactive power change load faster, easily causes voltage flicker phenomenon, leads to illumination flicker to affect one's power of vision, causes reality Test instrument or essence point manufactures etc. that sensitiveness load cannot normal work etc..Theory deduction, simulating, verifying, engineering practice all show, Svc due to response speed restriction it is impossible to follow the tracks of fast-changing load or burden without work, so to flickering phenomenon governance role fail to understand Aobvious., because postponing to control using Trigger Angle, reality output will be late by input reference, and single-phase tcr maximum is prolonged taking tcr type svc as a example Chi WeiThe svg response time depends on inductance, the time constant of resistance branch, and generally several milliseconds (it is contemplated herein that idealize mould Type, the response time in engineering also slightly postpones).

At present, how to jointly control svc and svg so as to not only enable reactive-load compensation purpose, and meet and become to quick Change idle accurate tracking to improve voltage flicker phenomenon, be a problem with engineering application value.

Content of the invention

Goal of the invention: for above-mentioned prior art, propose a kind of svg based on reactive power fluctuation frequency partition and svc and coordinate Control method, not only realizes reactive-load compensation purpose, and meets the accurate tracking idle to quick change to improve voltage flicker Phenomenon.

Technical scheme: a kind of svg based on reactive power fluctuation frequency partition and svc control method for coordinating, comprise the following steps:

(1), collection compensates point voltage u, electric current i, calculates reactive-load compensation demand q_c；

(2), gather svg output current i_svg, with given limit value i_lRelatively, if i_svg＜ i_l, then execution step (3), if i_svg ≥i_l, execution step (6)；

(3), to described reactive-load compensation demand q_cIt is filtered processing, low frequency component q_dThe reference compensating as svc, high frequency Component q_chThe reference compensating as svg；

(4), computing system power factor η and compensation point voltage flicker value p_st, such as meet relevant criterion, then return execution Step (1), otherwise execution step (5)；

(5), adjust the cut-off frequency of filtering process in described step (3), be then back to execution step (1)；

(6), enter the preferential compensation model of svc and carry out timing, described reactive-load compensation demand q_cThe ginseng compensating as svc Examine, described reactive-load compensation demand q_cWith svc reality output q_svcDifference (q_c-q_svc) as svg compensate reference；

(7), judge whether the working time t under the preferential compensation model of svc is more than given time limit t_lIf, t ＞ t_l, then hold Row step (1), if t≤t_l, then execution step (8)；

(8), collection compensates point voltage u, electric current i, calculates reactive-load compensation demand q_c, execution step (6).

Beneficial effect: because cost reason in engineering, the configuration capacity of svc is generally large, svg configuration capacity is general relatively Little, but it is limited to response speed factor, svc is not improved effect to flickering, and svg is significantly improved to flickering.If Only configure svg according to reactive compensation capacity, bring Cost Problems again, one kind proposed by the present invention is based on reactive power fluctuation frequency partition Svg and svc control method for coordinating, reactive power is filtered process, low frequency component is relatively slow by Large Copacity, response Svc compensates, and high fdrequency component is compensated by low capacity, the comparatively faster svg of response, and according to system power factor and compensation point voltage Flickering value real-time adjustment filter cutoff frequency；Monitor svg output current simultaneously, when its output is close to rated capacity, switching To the preferential compensation model of svc.The inventive method has taken into account svc unit capacity low cost but response speed is slow, svg fast response time But the feature of unit capacity high cost, learns from other's strong points to offset one's weaknesses, svc and svg is achieved with effective coordination and controls, both achieved idle benefit Repay purpose, and meet the accurate tracking idle to quick change to improve voltage flicker phenomenon.This invention is to quick change no Work(causes the power quality controlling of voltage flicker occasion, has certain Engineering Guidance meaning.

Brief description

Fig. 1 is svc and svg hybrid compensation electric arc furnaces load circuit figure in embodiment；

Fig. 2 is that in embodiment, svc and svg coordinates control structure schematic diagram；

Fig. 3 is the inventive method svc and svg control method for coordinating flow chart.

Specific embodiment

Below in conjunction with the accompanying drawings the present invention is done and further explain.

So that the voltage flicker to electric arc furnaces circuit is administered as a example, as shown in figure 1, svg is arranged on nearly mains side, svc installs In nearly electric arc furnace side, combine the reactive power to electric arc furnaces consumption and compensate.

System control principle as shown in Fig. 2 compensation point installs voltage transformer pt, install by svc output end, svg output end The output of pt and ct is converted to data signal by ad modulus conversion chip by current transformer ct, and dsp is responsible for calculating idle need Ask, filtering process, calculating power factor and voltage flicker value, calculating svc and svg compensate science and engineering at the volume of data such as reference Make, fpga produces the trigger pulse of svc and svg according to the output of dsp.Control method step is as follows:

(1), collection compensates point voltage u, electric current i, calculates reactive-load compensation demand q_c: according to Instantaneous Power Theory, there is q_c=u_β i_α-u_αi_β；In formula,

$\left[\begin{array}{c}{u}_{\mathrm{\α}}\\ u_{\mathrm{\β}}\end{array}\right]=\sqrt{\frac{2}{3}}\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \frac{\sqrt{3}}{2}& -\frac{\sqrt{3}}{2}\end{array}\right]\left[\begin{array}{c}{u}_a\\ u_b\\ u_c\end{array}\right]$

$\left[\begin{array}{c}{i}_{\mathrm{\α}}\\ i_{\mathrm{\β}}\end{array}\right]=\sqrt{\frac{2}{3}}\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \frac{\sqrt{3}}{2}& -\frac{\sqrt{3}}{2}\end{array}\right]\left[\begin{array}{c}{i}_a\\ i_b\\ i_c\end{array}\right]$

u_a、u_b、u_cFor the three-phase voltage of compensation point, i_a、i_b、i_cThree-phase current for compensation point；

(2), collection svg output current i now_svg, with given limit value i_lRelatively, if i_svg＜ i_l, then execution step (3), If i_svg≥i_l, execution step (6)；Wherein, given limit value i_lCan be set with margin of safety according to svg output current limit value；

(3), calculated reactive-load compensation demand q to step (1)_cIt is filtered processing, the low frequency that filtering process obtains Component q_dThe reference compensating as svc, high fdrequency component q that filtering process obtains_chThe reference compensating as svg；Svc and svg enters Row System Reactive Power compensates；

(4) now power factor η of system and compensation point voltage flicker value p, are calculated_st, as this two values all meet correlation Standard, then returns to execution step (1), otherwise execution step (5)；

(5), in set-up procedure (3) filtering process cut-off frequency f, be then back to execution step (1)；Wherein, frequency is adjusted Adjusting method can be to adjust cut-off frequency by preset fixed step size frequency adjusted value δ f, the cut-off frequency f '=f after adjustment +δf；

(6), enter the preferential compensation model of svc and carry out timing, calculated reactive-load compensation demand q of step (1)_cAs The reference that svc compensates, this reactive-load compensation demand q_cWith now svc reality output q_svcDifference (q_c-q_svc) compensate as svg Reference；Svc and svg carries out System Reactive Power compensation；

(7), judge whether the working time t under the preferential compensation model of svc is more than given time limit t_lIf, t ＞ t_l, then hold Row step (1), if t≤t_l, then execution step (8)；Wherein, given time limit t_lIt is worth by equipment user according to equipment situation with now Field needs to set；

(8), collection compensates point voltage u, electric current i, calculates reactive-load compensation demand q_c, execution step (6).

The method svc and svg are achieved effective coordinate to control, both achieved reactive-load compensation purpose, and meet right The accurate tracking that quick change is idle is to improve voltage flicker phenomenon.

The above is only the preferred embodiment of the present invention it is noted that ordinary skill people for the art For member, under the premise without departing from the principles of the invention, some improvements and modifications can also be made, these improvements and modifications also should It is considered as protection scope of the present invention.

Claims (1)

1. a kind of svg based on reactive power fluctuation frequency partition and svc control method for coordinating is it is characterised in that comprise the following steps:

(1), collection compensates point voltage u, electric current i, calculates reactive-load compensation demand q_c；

(2), gather svg output current i_svg, with given limit value i_lRelatively, if i_svg<i_l, then execution step (3), if i_svg≥i_l, Execution step (6)；

(3), to described reactive-load compensation demand q_cIt is filtered processing, low frequency component q_clThe reference compensating as svc, high fdrequency component q_chThe reference compensating as svg；

(4), computing system power factor η and compensation point voltage flicker value p_st, such as meet relevant criterion, then return execution step (1), otherwise execution step (5)；

(5), adjust the cut-off frequency of filtering process in described step (3), be then back to execution step (1)；

(6), enter the preferential compensation model of svc and carry out timing, described reactive-load compensation demand q_cThe reference compensating as svc, described Reactive-load compensation demand q_cWith svc reality output q_svcDifference (q_c-q_svc) as svg compensate reference；

(7), judge whether the working time t under the preferential compensation model of svc is more than given time limit t_lIf, t ＞ t_l, then execute step Suddenly (1), if t≤t_l, then execution step (8)；

(8), collection compensates point voltage u, electric current i, calculates reactive-load compensation demand q_c, execution step (6).