JPS5914023A - Method for controlling suppressing device of flicker - Google Patents

Abstract

PURPOSE:To stabilize a control operation, by inputting the synthesized value of current flowing into current transformers on the secondary sides of plural load transformers connected to a bus and the output of a transformer connected to the bus to a controller and controlling a flowing angle by the output of the controller. CONSTITUTION:The current transformers CT1-CTn are connected to the secondary sides of plural load transformers Tr1-Trn connected to the bus BUS and the current values are synthesized by a synthesized current signal generator TCT and applied to a controller CONT. The voltages of the bus BUS is lowered by a transformer PT and applied to the controller CONT. The output of the controller CONT controls the arc angle of an SCR connected to the secondary side of a transformer TrF for a flicker suppressing device to adjust the inflow current of reactor L. Consequently, voltage variation generated by the variation of loads L1-Ln is effectively suppressed by the geometrical effect of fixing capacitors C1, C2 and a stable operation is attained even at the time of a low load.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control method for a flicker suppression device comprising a shunt reactor whose phase is controlled by a thyristor and a fixed capacitor connected in parallel to the shunt reactor.

The conventional 7-flux suppression device consists of a fixed capacitor and a shunt reactor installed in parallel with the fixed capacitor, and the closing phase of the shunt reactor is as shown in the single line diagram in Figure 1.
Load transformer 'I'r+, 'I'r2---T
The messages from the current transformer OT, which detects the combined load current on the primary side of rn, and the transformer PT, which converts the bus voltage to low voltage, are input to the controller 0ON'l', and the output of the controller 0ONT is 7. 2 of the power suppressor transformer 'Irl'
It is determined by controlling the firing position of the thyristor 80R provided on the next side.

This increases or decreases the inflow current of the reactor, and
Voltage fluctuations caused by fluctuations in L+, I+2.

・ This is suppressed by the synergistic effect with the separately provided fixed capacitors 0.t and 02.

In this method, when the load is relatively light, the transformer becomes over-excited by the phase-advanced reactive component of the fixed capacitor, distorting the current waveform, and the thyristor SOR is controlled in response to this distorted current. Therefore, an abnormal phenomenon may occur, or in some cases, flicker may be promoted and an adverse effect may occur.

In other words, in general, in this method, the response speed of the controller 0ONT is fast, and when controlling each phase, the load transformer THET and the excitation current of 2-----4'rn are used to The flowing DC component is amplified and 0.1~
A large DC component of e and O alternately flows through the shunt reactor L at a period of about 1 second, which may result in loss of control.

The present invention was made for the purpose of eliminating the above-mentioned drawbacks, and it was discovered that the cause of uncontrollability was caused by the excitation current of the load transformer, and as a countermeasure, a method of detecting the load current was developed. Negative and load transformer TH.

Tr2-------- By performing the control from the secondary side of the Indicates ↓ sea urchin, load”＋
bz---42H load transformer Tr+, TF2
-------Current transformers OT1゜OT2---OTe+ are provided on the secondary side of Trn to detect each load current, and each current transformer OT+, 0'I'2-----OTrL is The signal is input to the composite current signal generator TOT that combines the signals, and the signal and the signal of the transformer FT that converts the bus voltage to low voltage are input to the controller 0ONT. Thyristor sO installed on the secondary side
By controlling the ignition position of 'R and increasing or decreasing the inflow current of reactor L, voltage fluctuations caused by fluctuations in load Ll, J---L7+ can be compensated for by separately provided fixed capacitor O+, 0.2. It is controlled by a synergist/pot. Each of the above current transformers 0 'I+, Q T2--
---Synthesizing current signal generator'l that combines OT and signals
'OT may be a composite current transformer, but an electronic circuit maintains a function that allows the current transformation ratio to be freely selected depending on the load of each line and other conditions.

As described above, according to the control method of the flicker suppression device according to the present invention, the DC component caused by overexcitation of the load transformer is not amplified and becomes uncontrollable, and the thyristor control is performed appropriately in response to load fluctuations. This makes it possible to increase the effectiveness and effectiveness of suppressing 7-point loss.

[Brief explanation of the drawing]

FIG. 1 shows a control method of a conventional flicker suppression device, and FIG. 2 shows a control method of the present invention. B TJ El---One bus, 0+, 02-1---
-Fixed capacitor, L---One-shunt handle, S O
R-----Thyristor, ----One transformer, Tr+
, Tr2-Trn----Negative N, M transformer, (1'r, Or T+, O'l'2----G
-'E'n----1 current transformer, 11.12-L'
N-Me 11 Load/Load/Patent Applicant Chugoku Denki Seizo Co., Ltd. Representative Kenzo Maruyama Department 1 Kuchihaji Z Deputy

Claims (1)

[Claims] In a power suppression device consisting of a shunt reactor whose phase is controlled by a thyristor according to a fluctuating load and a fixed capacitor connected in parallel to the shunt reactor, two of a plurality of load transformers connected to a busbar are A current transformer is provided on the next side, and the output current of each current transformer is applied to a composite current signal generator, and the output signal and the output signal of a separately provided transformer that converts the bus voltage to low voltage are A flicker suppression/device control method characterized by inputting an input to a controller and applying the output to a thyristor gate to control firing and position, and adjusting the current flowing into a shunt reactor.