JP2020162381A - Automatic voltage regulator - Google Patents

Abstract

To provide a thyristor type automatic voltage regulator capable of achieving an effective voltage adjustment operation by optimizing operating time characteristics of a tap switching operation for suppressing gradual voltage fluctuations and a tap switching operation for suppressing large and steep voltage fluctuations.SOLUTION: Timed characteristics is configured by combination of timed characteristics (integral time characteristics or combination of anti-time characteristics and fixed time characteristics) for each tap switching. Using a voltage adjustment relay for outputting a command to switch to a target tap position at once, a semiconductor tap switch is controlled.SELECTED DRAWING: Figure 1

Description

The present invention relates to a thyristor type automatic voltage regulator in which the operation time characteristic of tap switching is optimized.

In recent years, a large amount of renewable energy has been introduced toward the realization of a low-carbon society. In addition, due to the uncertainties in power supply caused by the 2011 off the Pacific coast of Tohoku Earthquake, the momentum for conversion to domestic renewable energy has further increased.

On the other hand, if a large amount of renewable energy is connected to the distribution system, sudden voltage fluctuations may occur. In the high-voltage distribution system, the tap switching transformer (LRT) and automatic voltage regulator (SVR) under load are controlled so that they are within the appropriate voltage range, but the interconnection of renewable energy to the high-voltage distribution system and It is difficult to deal with sudden voltage fluctuations caused by the mass introduction of household photovoltaic power generation.

Therefore, in recent years, a thyristor-type automatic voltage regulator (TVR), which is capable of responding to sudden voltage fluctuations and can perform voltage adjustment at high speed and frequently, has been attracting attention (see Non-Patent Document 1 below).

Aichi Electric Technical Report No. 33, published on March 23, 2013, p. 7-12

FIG. 5 shows the thyristor type high voltage automatic voltage regulator described in Non-Patent Document 1. In this device, the transformer connection is V-star-shaped, and the low-voltage circuit side of the voltage adjustment transformer ETr and the low-voltage circuit side of the series transformer STR inserted in series with the line are connected by a thyristor tap switcher. The combined indirect switching method is adopted.

The control device of this device is a GA that outputs a tap switching command signal according to the combination of the control unit that performs voltage adjustment control and protection control against external / internal failures of the device, and the control unit and the thyristor selected by the control unit. A control / GA unit consisting of a unit and a power supply unit, and an MC unit that opens and closes the electromagnetic contactors MC1 and MC2 according to a command from the control unit when the operation of this automatic voltage regulator is started, stopped, and when an external / internal failure protection operation is performed. It is composed of.

The thyristor type tap switch is a tap switching thyristor Th1 to Th6, current limiting fuses F1 and F2, a bridge thyristor Thb, and a current transformer CT installed between the bridge thyristor Thb and the current limiting resistor R. It is composed of a GU unit including a snubber circuit, a surge absorber, and a gate drive device, and receives a tap switching signal from the control device to turn on / open a predetermined thyristor element.

When adjusting the voltage of the distribution line with the conventional automatic voltage regulator configured as described above, the control unit of the control device performs analog processing of the captured voltage and current elements, A / D conversion, and digitally by the CPU. Performs arithmetic processing and selects a combination of psyllistas to be turned on / off in order to adjust the voltage of the distribution line to a preset reference voltage.

The thyristor combination command selected by the control unit is output to the thyristor type tap switcher, and the tap switching thyristor Th1 to Th6 and the bridge thyristor Thb are switched according to the command to switch the tap of the voltage adjustment transformer ETr. , Adjust the distribution line voltage to the reference voltage.

The voltage adjustment relay (90 relay) constituting the control unit of the control device has 7 tap points, and the voltage adjustment range is ± 300 [V] in 100 [V] steps. In addition, a skip tap switching function is added to switch taps at once for large voltage fluctuations.

The jump tap switching function enables jump tap switching of up to 4 taps (± 400 [V]), and jump tap switching operation that suppresses large and steep voltage fluctuations and 1-tap switching that suppresses gradual voltage fluctuations. By using the operation together, it is possible to quickly adjust the voltage against various voltage fluctuations.

Specifically, as shown in FIG. 6, the dead zone is 0, 1-tap switching is an integral timed characteristic, and 2 taps or more is a fixed time characteristic.

If such a thyristor type automatic voltage regulator (TVR) is used, unlike a load tap switching transformer (LRT) and an automatic voltage regulator (SVR), renewable energy is connected to a high-voltage distribution system or at home. It is possible to cope with sudden voltage fluctuations due to the mass introduction of photovoltaic power generation.

However, in the thyristor type automatic voltage regulator described in Non-Patent Document 1, as described above, switching of 1 tap is performed by the integration time limit characteristic, and switching of 2 taps or more is performed by the time limit characteristic, and thus is shown in FIG. As described above, when the voltage between taps is reduced (100 [V] → 67 [V]) in order to make finer voltage adjustment, tap switching is instantly executed from a small value of 67 [V] as the voltage fluctuation. Therefore, there is a drawback that the voltage adjustment operation is executed even in the voltage deviation where the request for voltage adjustment is low.

Therefore, in the present invention, effective voltage adjustment operation can be realized by optimizing the operation time characteristics of the tap switching operation that suppresses gradual voltage fluctuation and the tap switching operation that suppresses large and steep voltage fluctuation. Provide a thyristor type automatic voltage regulator that can be used.

The invention according to claim 1 is an automatic voltage adjusting device installed on a distribution line and adjusting a line voltage by tap switching, in which the tap switching means is switched to an arbitrary tap position at once by using a semiconductor switch such as a thyristor. In order to adjust the difference voltage between the line voltage and the settling voltage to a small value between the semiconductor tap switch that enables this, the semiconductor tap switch is set to the target tap position according to the time-limited characteristics of each tap switch. It is characterized in that voltage adjustment is performed using a voltage adjustment relay that outputs a command to switch each time.

The invention according to claim 2 is characterized in that, in the automatic voltage regulator according to claim 1, the voltage adjustment relay is a combination of a multi-stage integral time-time characteristic and a time-limited time characteristic corresponding to a tap voltage.

The invention according to claim 3 is characterized in that, in the automatic voltage regulator according to claim 2, the voltage adjusting relay has a fixed time characteristic only at the highest stage and an integral time characteristic at the other stages.

The invention according to claim 4 is characterized in that, in the automatic voltage regulator according to claim 1, the voltage adjustment relay is a combination of a multi-stage anti-time limit characteristic and a fixed time characteristic corresponding to a tap voltage.

The invention according to claim 5 is characterized in that, in the automatic voltage regulator according to claim 4, the voltage adjusting relay has a fixed time characteristic only at the highest stage and a counter time characteristic at the other stages.

In the invention according to claim 6, the three-phase voltage imbalance can be eliminated by using the automatic voltage regulator according to claims 1 to 5 as a three-phase Y connection or a two-phase V connection and controlling the voltage of each phase independently. It is characterized by being configured in this way.

According to the first aspect of the present invention, by using a voltage-adjusted relay that combines a time-limited characteristic corresponding to a multi-stage switching tap, it is possible to set an operation time characteristic of tap switching suitable for the magnitude of voltage fluctuation.

According to the invention according to claim 2, since the voltage adjusting relay is a combination of the multi-stage integral timed characteristic and the fixed time characteristic corresponding to the tap voltage, the tap switching can be performed instantly when the voltage fluctuation is small. It is possible to prevent the switching frequency from becoming excessive.

According to the invention of claim 3, since only the highest stage has a fixed time characteristic and the other stages have an integral timed characteristic, tap switching can be performed instantly when the voltage fluctuation is large.

According to the invention of claim 4, since the voltage adjustment relay is a combination of a multi-stage anti-time limit characteristic and a fixed time characteristic corresponding to the tap voltage, tap switching can be performed instantly when the voltage fluctuation is small. It is possible to prevent the switching frequency from becoming excessive.

According to the invention of claim 5, since only the highest stage has a fixed time characteristic and the other stages have a counter time characteristic, tap switching can be performed instantly when the voltage fluctuation is large.

According to the invention of claim 6, since the automatic voltage regulator is configured to have a three-phase Y connection or a two-phase V connection and each phase is independently voltage-controlled, the three-phase voltage imbalance is eliminated. Can be done.

It is a graph which shows the tap switching operation time characteristic of the automatic voltage regulator which concerns on 1st Embodiment of this invention. It is a graph explaining the method of realizing the tap switching operation time characteristic (1 to 3 tap switching) according to the first embodiment of the present invention. It is a graph explaining the method of realizing the tap switching operation time characteristic (4 to 6 tap switching) according to the first embodiment of the present invention. It is a graph which shows the tap switching operation time characteristic of the automatic voltage regulator which concerns on 2nd Embodiment of this invention. It is a block diagram which shows the structure of the conventional automatic voltage regulator. It is a graph which shows the tap switching operation time characteristic which concerns on the conventional automatic voltage regulator. It is a graph which shows the tap switching operation time characteristic when the voltage between taps of a conventional automatic voltage regulator is reduced.

Example 1 of the present invention will be described with reference to FIG. Since the circuit configuration and operation of the thyristor type automatic voltage regulator according to the present invention are substantially the same as those of the conventional thyristor type automatic voltage regulator described above, FIG. 5 will be described below in combination.

In the automatic voltage regulator of the present invention as well as the conventional thyristor type automatic voltage regulator, the voltage and current elements of the distribution line are taken in by the control unit of the control device shown in FIG. 5, and then analog-processed to perform A / After the D conversion, the CPU performs digital arithmetic processing.

After that, the control unit selects a combination of thyristors to be turned on / off in order to adjust the voltage of the distribution line to a preset reference voltage.

The thyristor combination command selected by the control unit is output to the thyristor type tap switcher via the GA unit or the like. The thyristor type tap switch adjusts the distribution line voltage to the reference voltage by switching the thyristors Th1 to Th6 and the bridge thyristor Thb in response to the command and switching the taps of the voltage adjusting transformer ETr.

FIG. 1 shows the time-limited characteristics of the voltage adjusting relay (90 relay) constituting the control unit. FIG. 1 shows the time limit characteristics corresponding to each tap switching when the voltage adjustment range is set to 13 tap points in the ± 400 [V] and 67 [V] steps. In FIG. 1, a dead zone ± 47 [V] is provided in order to reduce the switching frequency of the thyristors Th1 to Th6 and Thb, and a jump tap function of 2 to 6 taps is added.

The voltage adjustment relay (90 relay) having the time-limited characteristics shown in FIG. 1 meets the demand for finer voltage adjustment by applying it to a TVR capable of voltage adjustment of ± 400 [V] with 13 tap points. It is possible.

According to the voltage adjustment relay (90 relay) having the time limit characteristic shown in FIG. 1, the 1 to 3 tap switching that suppresses the relatively gradual voltage fluctuation is executed with the integral time limit characteristic, and the voltage fluctuation is large and steep. The switching operation of suppressing 4 to 6 taps is executed by the jump tap switching of the fixed time characteristic.

As shown in FIG. 1, when the voltage between taps is reduced (67 [V]) in order to make finer voltage adjustment, only one tap switching is set as the integration time limit characteristic as shown in FIG. 7, and switching of two or more taps is performed. If is set to the fixed time characteristic, for example, 2-tap switching is instantaneously executed for a small voltage fluctuation of about 70 [V]. As a result, the voltage adjustment operation is frequently executed even in the voltage deviation where the request for voltage adjustment is low.

Therefore, when reducing the voltage between taps (67 [V]) in order to make finer voltage adjustment, as shown in FIG. 1, the voltage adjustment is requested by setting the 1 to 3 tap switching as the integration time limit characteristic. Tap switching is suppressed as much as possible for small voltage fluctuations that are relatively low, and voltage adjustment is performed instantly by setting a fixed-time characteristic for steep voltage fluctuations that require tap switching of 4 taps or more. It becomes possible.

Next, as shown in FIG. 1, a method of controlling the time-limited characteristics of the voltage adjusting relay (90 relay) as a combination of the multi-stage integral time-limited characteristics and the fixed-time characteristics will be described with reference to FIGS. 2 and 3.

As shown in FIGS. 2 and 3, the voltage adjustment relay (90 relay) of the present invention is realized by incorporating the time limit characteristics corresponding to each tap switching into the software (program), and controls by combining these time limit characteristics. By doing so, the time-limited characteristics of 1 to 6 taps shown in FIG. 1 are realized.

That is, FIG. 2A shows the dead zone as ± 47 [V] and the time limit corresponding to 1-tap switching as the integral time characteristic, and FIG. 2B shows the dead zone as ± 113 [V] and 2 taps. The time limit characteristic corresponding to the switching is the integral time limit characteristic.

Further, FIG. 3C shows the dead zone as ± 180 [V] and the time characteristic corresponding to 3-tap switching as the integral time characteristic, and FIG. 3D shows the dead zone as ± 247 [V] and 4 The time-limited characteristics corresponding to tap switching are defined as the time-limited characteristics.

Further, FIG. 3 (e) shows the dead zone as ± 313 [V] and the time characteristic corresponding to 5-tap switching as the fixed time characteristic, and FIG. 3 (f) shows the dead zone as ± 380 [V] and 6 The time-limited characteristics corresponding to tap switching are defined as the time-limited characteristics.

The control unit of the control device shown in FIG. 5 realizes the time-limited characteristics corresponding to each tap switching by software as described above, and by controlling these in combination, it is possible to realize the time-limited characteristics shown in FIG. It becomes.

Controlling in combination means controlling the tap up / down command required to set the distribution line voltage to the reference voltage according to the time-limited characteristics shown in FIGS. 2 and 3 based on the voltage and current elements taken in by the control unit. The GA section outputs the combination command of the thyristor corresponding to the input command to the thyristor type tap switcher.

When a plurality of tap switching commands conflict with each other in the control unit, for example, the one with the larger number of switching taps is given priority and the corresponding thyristor combination command is output to the thyristor type tap switching device.

Subsequently, the second example of the present invention will be described with reference to FIG. The voltage adjustment relay (90 relay) shown in FIG. 4 has a voltage adjustment range of ± 400 [V], 67 [V] steps with 13 tap points, and a dead zone of ± 47 [V] with a jump tap function (2 to 6). (At the time of tap switching).

According to the voltage adjustment relay (90 relay) of FIG. 4, 1 to 5 tap switching is an integral timed characteristic, and only the highest tap switching is a fixed time characteristic.

With this configuration, the voltage can be instantly adjusted to the reference voltage only when a large voltage fluctuation of 380 [V] or more occurs, and the voltage deviation becomes large when the voltage fluctuation is less than that. Since the tap switching can be executed by gradually shortening the operation time according to the above, it is possible to adjust the voltage in a short time in a situation where voltage adjustment is indispensable while suppressing unnecessary tap switching operation as much as possible.

The time-limited characteristics shown in FIG. 4 are also realized by the control methods described in FIGS. 2 and 3.

In the first and second embodiments described above, the case where the time limit characteristic of the voltage adjustment relay (90 relay) is a combination of the integral time limit characteristic and the limit time characteristic has been described, but instead of this combination, the counter time limit time The same effect as described above can be obtained as a combination of the characteristic and the fixed time characteristic.

In addition, the method of combining the counter-time characteristic and the fixed-time characteristic is also realized by incorporating the time-time characteristic corresponding to each tap switching into the software as shown in FIGS. 2 and 3, and the time-limited characteristic corresponding to each tap switching is combined. It is clear that it can be achieved by controlling it.

In the first and second embodiments described above, it has been explained that the time-limited characteristics shown in FIGS. 1 and 4 are realized by incorporating the time-limited characteristics corresponding to each tap switching into the software and controlling them in combination. The invention is not limited to the case where it is realized by software, but it can also be realized by combining a plurality of hardware having each time-limited characteristic, and it is natural that the invention is included in the technical scope of the present invention.

Further, in the first and second embodiments described above, as shown in FIGS. 1 and 4, the case where the dead zone is provided has been described, but by not providing the dead band, the voltage adjustment accuracy to the reference voltage is improved. It may be configured as.

Further, in the above-mentioned automatic voltage regulator according to the present invention, the voltage regulator ETr is V-connected, the series transformer STR is Y-connected, and the thyristor tap switcher is V-connected voltage-regulated transformer ETr indirect circuit. Since it is configured to be connected to each phase (two phases) on the side, it is possible to improve the three-phase voltage imbalance by operating the thyristor type tap switcher individually for each phase.

In order to improve this voltage imbalance, a high voltage imbalance can be improved by connecting a voltage monitoring phase to the maximum voltage phase and the minimum voltage phase of the three-phase voltage when the automatic voltage regulator of the present invention is installed. It becomes possible.

Further, by independently tap-switching each phase (two-phase) with a thyristor-type tap switcher, it is possible to independently adjust the voltage of each phase (two-phase) to improve the three-phase voltage imbalance.

As described above, according to the automatic voltage adjusting device of the present invention, the operation time characteristics of the tap switching operation that suppresses a gradual voltage fluctuation and the tap switching operation that suppresses a large and steep voltage fluctuation are optimized. While suppressing the voltage adjustment operation due to unnecessary tap switching for small voltage fluctuations, the voltage can be adjusted instantly for large voltage fluctuations, and effective voltage adjustment operation can be realized.

In particular, by combining the operating time characteristics of the tap switching operation with the integral timed characteristics or the counter-timed characteristics and the fixed time characteristics, the operating time characteristics can be optimized, and problems occur or limit due to excessive tap switching frequency. Problems such as temperature rise of flow resistance can be solved.

Further, the integration time characteristic or the counter time characteristic and the time time characteristic can be realized by controlling the time limit characteristic for each tap switching in combination.

It can be used for thyristor type automatic voltage regulators.

STR Series Transformer Etr Voltage Adjusting Transformer VT, CT Transformer Th1 ~ Th6 Tap Changer Thyristor Thb Bridge Thyristor F1 ~ F2 Current Limiting Fuse R Limiting Resistance MC Electromagnetic Contactor

Claims (6)

In an automatic voltage adjusting device installed on a distribution line and adjusting the line voltage by tap switching, the tap switching means can be switched to an arbitrary tap position at once by using a semiconductor switch such as a thyristor. A voltage that outputs a command to the semiconductor tap switcher to switch to the target tap position at one time according to the time-limited characteristics of each tap switch in order to adjust the difference voltage between the device and the line voltage and the set voltage to a small value. An automatic voltage regulator characterized by switching to a tap for voltage adjustment using an adjustment relay to adjust the voltage. The automatic voltage adjusting device according to claim 1, wherein the voltage adjusting relay is a combination of a multi-stage integral timed characteristic and a fixed time characteristic corresponding to a tap voltage. The automatic voltage adjusting device according to claim 2, wherein the voltage adjusting relay has a constant time characteristic only at the highest stage and an integration time characteristic at the other stages. The automatic voltage adjusting device according to claim 1, wherein the voltage adjusting relay is a combination of a multi-stage anti-time-time characteristic and a fixed-time characteristic corresponding to a tap voltage. The automatic voltage adjusting device according to claim 4, wherein the voltage adjusting relay has a fixed time characteristic only at the highest stage and a counter time characteristic at the other stages. Claims 1 to 1, wherein the automatic voltage regulator is configured as a three-phase Y connection or a two-phase V connection so that the three-phase voltage imbalance is also eliminated by controlling the voltage of each phase independently. The automatic voltage adjusting device according to claim 5.

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