JPH04178117A - Control system for voltage fluctuation suppressor - Google Patents

Abstract

PURPOSE:To improve response of AVR control system by providing a TCR control section with a continuous control section and a step control section so that the TCR control section can respond quickly even to a sporadic instantaneous overvoltage or low voltage, conducting priority control through the step control section at the time of compensation of sporadic voltage fluctuation and performing phase control of a thyristor based on a signal fed from the step control section. CONSTITUTION:When instantaneous voltage drop occurs in a step control section 18 additionally provided to a continuous control section 17 and the voltage Vl has dropped below 95% of system voltage, a comparator 29 functions to turn a relay X2 ON and a phase delay setting component 31 is added to an adder 19. Consequently, a phase delay component is added to the input of 9 to increase the firing angle betaof a thyristor at TCR section and thereby the current conducting through a reactor at the TCR section decreases thus boosting the system voltage. In similar manner, when an instantaneous voltage rise occurs and the Vl exceed over 105% of the system voltage, a comparator 28 functions to lower the system voltage. According to the system, transient power supply voltage fluctuation can be suppressed quickly by additionally providing a step control section.

Description

[Detailed description of the invention] [Field of application for business owner M] The present invention provides voltage control in a voltage fluctuation suppressing device using a thyristor-controlled reactor system, which is installed for the purpose of suppressing voltage fluctuations in a power system that has variable loads such as AC regenerative vehicles. Control of a voltage fluctuation suppressing device, which comprises a continuous control section and a stepwise control section, and in particular, the stepwise control is given priority to compensate for sudden voltage fluctuations such as instantaneous overvoltage and undervoltage. Regarding the method.

[Prior art] Figure 3 shows automatic voltage control (hereinafter referred to as VR control) for stabilizing the voltage of the power system against fluctuating loads such as AC regeneration vehicles.
An example of the method is shown below. Corresponding to the load 4 such as an AC regeneration vehicle loaded on the feeder line 3 connected to the power source 1, a thyrisk switch 14 in which a reactor 13 and a thyristor are connected in anti-parallel to the feeder line 3 or the same level track is installed. Thyristor-controlled reactors connected in series! 2 (hereinafter referred to as 701 section), and a harmonic filter section I5 is connected in parallel with this. Note that 2 is the percent impedance on the power supply side (
%2). This %2 is proportional to the voltage variation (ΔV).

To create the ignition control phase pulse to the 701 section 12,
PT5 is connected to feeder line 3 or the same level line,
A voltage detector 6 for detecting the feeding voltage is connected to this secondary side.

In a circuit with this type of configuration, at this time, TCRIB
12 controls the phase of the cyrisk switch 14 and activates it! 3 is placed in a state where a rated current (slow phase current) is applied, and the feeder line is maintained at the rated voltage.

Therefore, when there is no load 4, the rated voltage v of the feeder line 3
An equal reference value Vref is set corresponding to the detected voltage signal Vl based on L, and the difference signal ΔV is obtained by the voltage fluctuation adder 7, and the difference signal ΔV is P! The output is input to a controller 8 to be controlled, and its output is input to a function circuit 9. In the function circuit 9, in order to compensate for fluctuations in ΔV by changing the current flowing through the reactor 13, the voltage signal is converted into a voltage signal corresponding to the firing phase angle of the thyristor that generates the current, and is output to the next control pulse generator. Synchronous power supply circuit input to 10 and connected to Pτ5! 6, a thyristor phase control pulse corresponding to the ignition control phase angle is outputted by the synchronization signal S. This control pulse is applied to transformer 11
is output to the gate terminal of the thyristor 14 via the thyristor, which fires at its phase control angle.

In this way, when the load 4 changes from a non-existent state to a present state, the reactive power of the load increases and the feeding voltage drops. At this time, the output from adder 7 becomes large, and P! The output from the controller 8 increases, and due to the increase in the input to the funxilon circuit 9, the phase of the firing pulse of the thyristor in the pulse transformer 11 is delayed, so that the current flowing in the reactor 13 decreases, From the perspective of the power grid, the idle component has the same capacity as before the load change, and the grid voltage is controlled to a constant voltage.

[Problem to be solved by the invention] By the way, the control constant of the AVR control system at this Enoki load is:
Since the loop steady-state deviation several percent target and the loop time constant of about 0.1S are the stable operating region of the control system, sudden instantaneous overvoltage,
In principle, it cannot be ruled out that the response to low voltages is delayed.

[Means for Solving the Problems] The present invention provides a continuous control section and a stepwise control section in the TCR control section so as to be able to quickly respond to sudden instantaneous, overvoltage, and low voltage as described above. To compensate for the sudden voltage fluctuation, the stepwise control section is prioritized and the phase of the thyristor is controlled using this signal, thereby improving the response performance of the conventional AYR control system.

The present invention will be explained below with reference to an example of a circuit block of the present invention shown in FIG. 1 and FIG. 2 showing a detailed circuit of FIG. 1.

The same parts as in FIG. 3 are indicated by the same reference numerals.

As shown in FIG. 1, a feeder wire 3 is connected to a power source 1.

Electric power is supplied from this feeder line 3 to a load 4 such as a regenerative vehicle.

Thyrisk switch with thyristors connected in anti-parallel to feeder line 3 or the same level line! 4 and a reactor 13 are connected in series to form a TCR section I2, and filter sections 15 for absorbing each harmonic are installed in parallel with the TCR section. In order to control the energization of the TCR section 12, a PT5 is connected to the feeder line 3 or a line at the same level, and the PT5 is connected to the voltage detector 6 and to the synchronous power supply circuit IG. The voltage detector 6 has a continuous control section 17 and a stepwise control section 8.
connected to. The voltage detection signal (V) detected by the voltage detector 6 is input to the continuous control section 17 and step control section 16. Details of the continuous control section 17 and step control section 18 will be described later with reference to FIG. When the feeding voltage varies slowly, the control voltage signal from the continuous control section 17 is applied to the adder 1.
9, which is converted into a control voltage signal corresponding to the negative phase of the firing phase by the function circuit 9, and its output is converted to the firing phase angle of the thyristor by the pulse generator 10 according to the reference signal from the power supply synchronization circuit 16. converted and generates a pulse. This firing phase angle pulse is transmitted to amplifier 21. The reactor is sent via the pulse transformer 22 to the thyristor switch 13 and controlled by the thyristor! 2 continuous energization control is performed.

On the other hand, when the feeding voltage suddenly changes instantaneously, the step control section 18 outputs a signal, and this signal is summed with the output signal from the continuous control section +7 side in the adder 19 and output. The voltage signal is converted into a voltage signal corresponding to the ignition phase angle by the switch circuit 9, and the energization of the TCR section 12 is controlled as described above.

The control section consisting of the continuous control section 16 and the stepwise control section 17 will be explained below with reference to FIG. Note that the same parts as in FIG. 1 are indicated by the same symbols.

The fluctuating feeder line voltage signal V from the voltage detector 6! is input, the difference voltage between the reference value Vrefl and Vl from the reference value setting circuit 23 is determined by the adder 24, and this difference output is used as the PI
Adder through m-segment 1?1! 9 is a continuous control section, and this Vl and Vref2 (1,05pu setting) or Vref3 (0,95pu setting) and comparator 2
8 or 29, for example, an instantaneous voltage drop occurs and v
When I becomes 95% voltage or less (0.95 pu), the comparator 29 operates, and the 121J relay (an electronic switch may also be used), which turns on at 10, turns on. (0,025Pu)31 is added to the adder 19 via the adder 32. As a result, the slow phase bone is added to the input of 9, and the firing angle β of the TCR thyristor becomes large.
The current flowing through the accelerator of the TCR section is controlled to decrease and the grid voltage is increased.

Similarly, when an instantaneous voltage rise occurs and Vl becomes 105% or more (1.05 pu), the comparator 28 operates,
The LIJ relay that turns on at 10 turns on, and at this contact a, Δ
The phase advance setting (0,025 pu) 30 is added to 13 through an adder 32. As a result, the leading phase is added to the input of 8, the firing angle β of the TCR thyristor becomes small, and T
The current flowing through the CR section saddle increases and the system voltage is controlled to decrease.

The aforementioned Δ slow phase setting and Δ advanced phase setting are each 0.025p.
The reason for selecting u is to consider the hysteresis characteristics in cooperative control with continuous control and stepwise control. The role of continuous control and stepwise control is that in this example, the continuous control system gives priority to suppressing voltage fluctuations of 35% to 105%, and the suppression of voltage fluctuations of 35% to 105%
For voltage fluctuations of 5% or more, step control is given priority.

[If the operating voltage drops slowly below the rated voltage, PI controller 17! A control signal is output, and the feeding voltage is corrected in the direction of the rated voltage, but there is a rapid transient voltage fluctuation, and the feeding voltage drops to 0.95V! When it is turned off, a control signal for lowering the reactor current by 0.025 pu is output from the level setter (Δ slow phase setting) 31 to the adder 32 in response to the rising signal from the comparator 29, and is input to the adder 19.

Even in this state, if the feeding voltage v1 further drops, the output of the PI controller 171 adds a delayed phase signal to the adder 19. In other words, the continuous control system can follow the electric voltage by 0.95V! Control so that the above is achieved. Feeding voltage is 0.95V1 or more (t
, osvl or less), the aforementioned comparator 29 becomes inactive, and the feeding voltage changes to PI controller! 711, that is, the control operation is performed only in the continuous control system.

Similarly, the feeding voltage is 1.05v! When the value is above, a control signal for increasing the reactor current by 0.025 pu is output from the level setter (Δ advance setting) 30 to the adder 32 in response to the rising signal from the comparator 28, and is input to the adder 19.

Even in this state, the feeding voltage is V! If increases further, P! The output of the controller 171 adds a phase advance signal to the adder 19. That is, the continuous control system can follow and control the electric voltage to be 1.05v1 or less.

When the feeding voltage becomes 1.05 Vj or less (0.95 V! or more), the aforementioned comparator 28 becomes inoperative, and the feeding voltage becomes PI311 Node 171. In other words, the control operation is performed only by the continuous control system. The reason why the stepwise control system performs priority control is that there is no time delay in comparators 2B and 29, and the PI of the continuous control system
This is because the controller 171 needs to have a time element.

FIG. 5 shows the control results of the conventional automatic voltage control system for the TCH shown in FIG. As shown in the figure, for example, sudden voltage fluctuations due to disconnector opening/closing surges, etc.
Since the response of 7l is slow and does not respond to fast fluctuations, sudden voltage cannot be suppressed.

On the other hand, FIG. 4 shows an example of suppressing fluctuations in the case of a decrease in the feeding voltage using a control method including a stepwise control section.

The operating speed of the stepwise control section in the present invention is 1/10 of the operating speed of the continuous control section, and the figure shows that the voltage fluctuation can be suppressed by adapting to sudden voltage fluctuations in the grid voltage.

[Effects of the Invention] As explained above, according to the control method of the present invention, by adding a stepwise control section to the response delay that is the principle of conventional system automatic voltage control, transient power fluctuations can be speeded up. Can be suppressed.

[Brief explanation of drawings]

FIG. 1 shows an embodiment of the present invention in a block diagram, and FIG. 2 shows a control section of the embodiment in FIG. 1 in a block diagram. FIG. 3 shows a block diagram of an automatic system voltage control device using a conventional thyristor-controlled reactor. FIG. 4 and FIG. 5 show grid voltage suppression waveforms in the present invention and the conventional control system. 1...Power supply, 4...Load, 5...PT18...
Voltage detector, 9... Functs 1f circuit, to...
Pulse generator, 11... Pulse transformer, 12...
TCR section, 13...Reactor, 14...Sirisk switch, 15...Filter section, 18...Power synchronization circuit, 17...Continuous control section,! 8... Step control unit, 23... Reference value setting circuit, 28.29... Comparator, 19.24.32... Adder, 30.31.
...Setting device (phase leading, slowing), 171...PI controller. '141!1 / Rolling j 1B5 with pressure 1 degree lower

Claims (1)

[Claims] (1) For a variable load connected to the grid, a thyristor-controlled reactor installed in the grid is used to control the energization of the thyristor-controlled reactor for a device that suppresses grid voltage fluctuations caused by the load. The control unit that detects the fluctuating voltage and continuously controls the energization of the reactor includes a step control unit that detects the fluctuating voltage of the system in stages and controls the energization of the reactor in a stepwise manner. and a control method for a voltage fluctuation suppressing device that quickly suppresses transient voltage fluctuations in the system voltage.