JP6666295B2 - Thyristor type automatic voltage regulator - Google Patents

Description

  The present invention relates to a thyristor-type automatic voltage regulator attached to a distribution line, significantly increasing the number of tap points, and equalizing the voltage between taps, thereby enabling feedback control of the voltage of the distribution line. The present invention relates to a technology for adjusting distribution line voltage without using a timed or integral type voltage adjusting relay.

  In recent years, the mass introduction of renewable energy has been promoted for realizing a low-carbon society. When a large amount of renewable energy is connected to a distribution system, a sudden voltage fluctuation may occur.

As a device capable of coping with such a rapid voltage fluctuation, a thyristor-type automatic voltage regulator exemplified in Non-Patent Document 1 given below has attracted attention.

"Catalog of Thyristor Type Automatic Voltage Regulator", Aichi Electric Co., Ltd., created in November 2016, [Searched on February 23, 2017], Internet <http://www.aichidenki.jp/products/catalog_pdf/tvr. pdf>

  The thyristor-type automatic voltage regulator includes a series transformer inserted in series on a distribution line, a voltage adjustment transformer inserted between distribution lines, tap switching thyristors Th1 to Th6, and a bridge thyristor Thb. A thyristor-type tap changer, a current-limiting resistor R connected to the thyristor Thb for bridge, and the like are provided, and power is distributed by rapidly and frequently switching the thyristor for tap change in response to sudden voltage fluctuations. It is possible to control the voltage of the system to fall within an appropriate range.

  Note that the above configuration is a configuration around one line. The connection system between the voltage adjusting transformer and the series transformer is a V-star system, but there are also a VV system and a star-star system. However, the present invention is a technique that can be applied irrespective of the functions of the thyristor-type automatic voltage regulator, such as the connection method and the three-phase unbalance suppression function.

  In the thyristor-type automatic voltage regulator having the above-described configuration, a total of seven thyristors Th1 to Th6 for tap change and one thyristor Thb for bridge are included in the thyristor-type tap changer. In this case, as shown in FIGS. 3A and 3B, the number of taps for voltage adjustment was only seven at maximum.

  For this reason, when the voltage adjustment range is ± 300 V, the voltage between the taps for voltage adjustment is 100 V, and the step voltage is coarse with respect to the voltage adjustment range, and fine voltage adjustment cannot be performed.

  Accordingly, the present invention provides a thyristor-type automatic voltage regulator by significantly increasing the number of tap points, reducing the step voltage with respect to the voltage adjustment range, and controlling switching of the thyristor so that the adjustment voltage increases and decreases finely and linearly. Is regarded as a substantially linear voltage amplifier, and an automatic voltage regulator capable of realizing a quasi-linear voltage control for performing feedback control of a distribution line voltage is provided.

The invention according to claim 1 includes a transformer, a thyristor-type tap changer, and a control device that are directly connected to a high-voltage distribution line, and is inserted in series with the low-voltage circuit side of the voltage adjustment transformer and the line. A thyristor type in which the low voltage circuit side of the series transformer is connected with the thyristor type tap switch, and the thyristor is switched so as to adjust the voltage of the distribution line to a preset reference voltage and the tap of the voltage adjusting transformer is switched. In the automatic voltage regulator, a voltage regulating relay incorporating a compensator having no integrator in the control device is used, and a tap turns ratio of a low voltage circuit side winding of the voltage regulating transformer is set to 1: 3: 2. It is characterized in that the combination of the voltage ratios constitutes a voltage adjustment tap voltage.

According to a second aspect of the present invention, in the first aspect of the present invention, a voltage control relay of a linear control that switches and controls a thyristor so that a voltage between taps for voltage adjustment becomes equal and a regulated voltage linearly increases and decreases is used. It is characterized by performing voltage control.

According to a third aspect of the present invention, in the first aspect or the second aspect of the present invention, the control device performs feedback control of the detected time average value of the distribution line voltage to appropriately adjust the voltage of the distribution line. It has a special feature.

The invention of claim 4, wherein, in the invention according to any one of claims 1 to 3, the control device is characterized in that the voltage is controlled by providing a dead zone to the voltage regulator relay quasi linear control.

The invention according to claim 5 is characterized in that, in the invention according to any one of claims 1 to 4 , the series transformer is any one of V connection, Δ connection, and star connection.

According to the first aspect of the present invention , the voltage can be directly adjusted to the upper and lower limits of the voltage adjustment range by using the voltage adjustment relay incorporating the compensator having no integrator in the control device. In addition, the number of turns between taps of the low-voltage circuit side winding of the voltage adjustment transformer is set as a ratio of different voltages of 1: 3: 2, and the voltage adjustment tap voltage is configured by a combination thereof, so that a large number of taps can be formed with a small number of thyristors. Ri Do is possible to utilize the number and it is possible to quasi linear control equal tap voltage.

According to the second aspect of the present invention, in the control device, there is provided a quasi-linear control voltage adjustment relay that switches and controls the thyristor so that the adjustment voltage is finely and linearly increased and decreased by making the voltage between taps for voltage adjustment equal. By using it, it became possible to regard the thyristor type automatic voltage regulator as an almost linear voltage amplifier.

According to the third aspect of the present invention, the time average value of the distribution line voltage detected by the control device is feedback-controlled without using the conventional fixed-time type or integral type voltage adjusting relay, so that the voltage of the distribution line is reduced. Can be properly adjusted in the shortest time.

According to the fourth aspect of the present invention, by providing a dead zone in the quasi-linear control voltage adjusting relay, it is possible to appropriately control the switching frequency of the thyristor.

According to the invention described in claim 5, the present invention can be applied regardless of the connection method of the automatic voltage regulator.

FIG. 3 is a circuit diagram around one line of a thyristor type automatic voltage regulator of the present invention. (A) is a circuit diagram showing a connection state between a thyristor and a voltage adjustment transformer constituting the thyristor type automatic voltage regulator of the present invention, and (b) is an ON state of the thyristor and an adjustment voltage (tap for voltage adjustment). 3 is a table showing a relationship between the voltages. (A) is a circuit diagram showing a connection state between a thyristor and a voltage adjustment transformer constituting a conventional thyristor-type automatic voltage regulator, and (b) is an ON state of the thyristor and an adjustment voltage (tap voltage for voltage adjustment). 3) is a table showing the relationship.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a circuit diagram showing a configuration of a thyristor-type automatic voltage regulator A according to the present invention installed between distribution lines (one per distribution line) of a distribution system. The automatic voltage regulator A shown in FIG. 1 includes a series transformer 2 (a high-voltage circuit side winding 2 a and a low-voltage circuit side winding 2 b) connected in series to a distribution line 1, and a low-voltage circuit side winding of the series transformer 2. 2b, a voltage adjusting transformer 3 (high-voltage circuit-side winding 3a and low-voltage circuit-side winding 3b), a low-voltage circuit-side winding 2b of the series transformer 2 and a low-voltage circuit-side winding of the voltage adjusting transformer 3. It is schematically constituted by a thyristor type tap changer 4 connected between the lines 3b and a short circuit prevention circuit 5 connected in parallel to the voltage adjusting transformer 3.

  The thyristor tap changer 4 is configured by connecting eight thyristors Th1 to Th8 in a bridge, and the short-circuit prevention circuit 5 is configured by connecting a bridge thyristor Thb and a current limiting resistor R in series.

  Protective fuses F1 to F3 for protecting the thyristors Th1 to Th8 from overcurrent are connected between the thyristor tap changer 4 and the voltage adjusting transformer 3. In parallel with the short-circuit prevention circuit 5, a switch (a switch having a large current capacity, such as an electromagnetic contactor) 6 that is turned on when the apparatus is abnormal is connected.

  When the voltage of the power distribution line fluctuates due to a load fluctuation or the like, the automatic voltage regulator A configured as described above receives a command signal output from a control device (not shown) to output the voltage of the power distribution line 1 and a preset reference voltage. Tap selection of the thyristor tap changer 4 is performed so as to reduce the difference. In response, tap switching by thyristors Th1 to Th8 is performed, and control is performed so that the voltage range of the power distribution system falls within an appropriate voltage range.

  When switching the thyristors Th1 to Th8, the thyristor Thb for bridge is turned on and the thyristors Th1 to Th8 are turned off. Then, the current flowing in any of the thyristors Th1 to Th8 is commutated to the current limiting resistor R, and the thyristors Th1 to Th8 are turned off. Thereafter, the thyristor to be switched on is turned on, and the thyristor Thb for bridge is turned off. As described above, the current flows through the current limiting resistor R every time the tap is switched, so that heat is generated in the current limiting resistor R and the temperature rises.

  FIG. 2A shows a connection state between each of the thyristors Th <b> 1 to Th <b> 8 and the voltage adjustment transformer 3. The case where the voltage adjustment range is ± 300 [V] is illustrated, and the tap voltage employs a different voltage composition ratio of 50 [V], 150 [V], and 100 [V].

  FIG. 2B shows the relationship between the on-states of the eight thyristors Th1 to Th8 shown in FIG. As shown in FIG. 2B, in the automatic voltage regulator A of the present invention, the thyristor-type tap changer 4 includes eight thyristors Th1 to Th8, and adjusts the voltage between the tap windings of the voltage adjustment transformer 3. By setting the voltages to 50 [V], 150 [V], and 100 [V], it is possible to draw out 13 taps with the same step voltage of 50 [V] between taps for voltage adjustment.

  That is, while the conventional automatic voltage regulator shown in FIG. 3 uses seven thyristors to draw out seven taps, eight thyristors realize 13 taps.

  As a result, the voltage between taps for voltage adjustment of the automatic voltage regulator A is １ ／ of that of the conventional automatic voltage regulator, so that finer voltage adjustment is possible, and so-called quasi-linear control closer to linear control is achieved. Can be realized.

  Further, if the voltage between taps for voltage adjustment of the automatic voltage regulator A according to the present invention is set to 100 [V] similarly to the conventional automatic voltage regulator, only two thyristors need to be added to increase the conventional voltage adjustment range to two. Voltage adjustment of ± 600 [V], which is twice as large, can be performed.

  The control device (not shown) constituting the automatic voltage regulator A according to the present invention includes a voltage regulating relay incorporating a compensator (a compensator having no integrator such as a proportional regulator) for feedback-controlling the distribution line voltage. used. By using this voltage adjustment relay, the voltage can be directly adjusted to the upper and lower limits of the voltage adjustment range and fine voltage adjustment can be performed, so that voltage control can be performed in the shortest time.

  In addition, the control device can control the voltage value closer to the voltage management standard of the distribution line by averaging the detected voltage of the distribution line 1 over time. In addition, since the detection voltage is smoothed, tap switching is not performed with a small voltage change, so that the number of tap switching is suppressed. As a result, tap switching is performed for a small voltage fluctuation, and a current flows through the current limiting resistor R each time the switching is performed. As a result, the temperature of the current limiting resistor R excessively increases, and tap switching cannot be performed. Can be reliably prevented.

  Further, the control device achieves the same effect as described above even by suppressing the switching frequency of the thyristor by providing a dead zone in the voltage adjustment relay of the quasi-linear control.

  FIG. 1 illustrates a case where the series transformer 2 is star-connected as the automatic voltage regulator A according to the present invention, but the automatic voltage regulator A according to the present invention is not limited to this configuration. , The series transformers 2 may be connected by V connection or Δ connection.

As described above, according to the automatic voltage regulator A of the present invention, compared to the conventional case,
Quasi-linear control was made possible by greatly increasing the number of tap points and equalizing the voltage between taps.

  Further, as can be seen from the above description, the present invention is a technology that can be applied irrespective of functions such as a connection method of an automatic voltage regulator and a three-phase unbalance suppression function.

  INDUSTRIAL APPLICATION This invention is utilized for the apparatus corresponding to the voltage fluctuation of a distribution system.

DESCRIPTION OF SYMBOLS 1 Distribution line 2 Series transformer 2a High-voltage circuit side winding of series transformer 2b Low-voltage circuit side winding of series transformer 3 Voltage adjustment transformer 3a High-voltage circuit side winding of voltage adjustment transformer 3b Low voltage of voltage adjustment transformer Circuit side winding 4 Thyristor type tap changer Th1 to Th8 Thyristor 5 Short circuit prevention circuit Thb Thyristor for bridge R Current limiting resistor 6 Switch A Thyristor type automatic voltage regulator

Claims (5)

It consists of a transformer, a thyristor tap changer, and a controller that are directly connected to the high-voltage distribution line.The low-voltage circuit side of the voltage-regulating transformer and the low-voltage circuit side of the series transformer inserted in series with the line A thyristor-type automatic voltage regulator that is coupled by the thyristor-type tap changer, switches a thyristor so as to adjust a voltage of a distribution line to a preset reference voltage, and switches a tap of the voltage adjustment transformer. A voltage regulating relay incorporating a compensator without an integrator is used in the device, and the tap turns ratio of the low voltage circuit side winding of the voltage regulating transformer is set as a ratio of different voltages of 1: 3: 2. A thyristor-type automatic voltage regulator characterized by comprising a tap voltage for voltage regulation.   The control device performs voltage control using a quasi-linear control voltage adjustment relay that switches and controls a thyristor so that the adjustment voltage increases and decreases linearly so that the voltage between taps for voltage adjustment becomes equal. The thyristor-type automatic voltage regulator according to claim 1.   3. The thyristor-type automatic voltage according to claim 1, wherein the control device performs feedback control on a time average value of the detected distribution line voltage to appropriately adjust the voltage of the distribution line. Moderator.   The thyristor-type automatic voltage regulator according to any one of claims 1 to 3, wherein the control device performs voltage control by providing a dead zone in a voltage adjustment relay of quasi-linear control.   The thyristor-type automatic voltage regulator according to any one of claims 1 to 4, wherein the series transformer is one of a V connection, a Δ connection, and a star connection.

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