JP6362756B1 - Excitation current suppression device - Google Patents

Abstract

It is possible to clarify the calculation method of the residual magnetic flux and specifically realize the excitation inrush current suppression of the single-phase transformer, and even if noise and harmonics are included in the single-phase voltage, Provided is a magnetizing inrush current suppressing device capable of accurately calculating a current phase angle and accurately determining a circuit breaker closing operation time.
An excitation inrush current suppressing device includes a transformer voltage measuring unit, a steady magnetic flux calculating unit, an effective breaking timing calculating unit, an effective residual magnetic flux calculating unit, and a closing phase angle calculating unit. A system voltage measuring unit 6, a current phase angle calculating unit 7, a closing command output unit 8, and a circuit breaker closing operation time calculating unit 9.
[Selection] Figure 1

Description

  The present invention relates to a magnetizing inrush current suppressing device for suppressing an magnetizing inrush current that is generated when a circuit breaker that opens and closes a connection between a single phase AC voltage power supply system and a single phase transformer.

  2. Description of the Related Art An excitation inrush current suppressing device is known as a device for eliminating a failure due to an excitation inrush current associated with transformer recharging. Patent Document 1 discloses an invention related to a magnetizing inrush current suppressing device for a three-phase transformer. This is a magnetizing inrush current suppression device having a mechanism for controlling a circuit breaker connected between a three-phase transformer and a system power supply, and includes a “voltage measurement unit”, an “effective interruption timing calculation unit”, and an “iron core magnetic flux calculation unit”. ”,“ Effective residual magnetic flux calculation unit ”,“ Plain phase angle calculation unit ”and“ Plain phase angle control unit ”, and“ Interrupt time calculation unit ”,“ Apparent residual magnetic flux calculation unit ”and“ Put operation ”as necessary The structure includes a “time calculation unit”, an “applied phase angle actual value calculation unit”, and an “instantaneous voltage drop amount calculation unit”. The present invention has a great feature in the method of measuring the residual magnetic flux, and has a great effect in that it suppresses the magnetizing inrush current using the applied phase angle calculated from the residual magnetic flux. However, the present invention is configured by an algorithm for a three-phase transformer and cannot be applied to a single-phase transformer as it is.

  On the other hand, Patent Document 2 discloses an invention related to a magnetizing inrush current suppressing device intended for application to a single-phase transformer. This relates to an inrush current prevention device for a single-phase transformer that prevents the occurrence of an inrush current when power is applied to a low-voltage single-phase transformer. “The power monitoring circuit connected to the primary power circuit of the transformer is In addition to detecting power on / off, a phase detection circuit connected to the primary power supply circuit of the transformer detects the phase angle of the power supply voltage when the power supply is cut off. A switching element that is turned off when the power supply is cut off is connected so that when it is detected that the power supply to the transformer is cut off, the phase angle of the power supply voltage when the power supply is cut off is stored. When it is detected that the power has been turned on again, the power-on timing for reducing the inrush current is obtained based on the power-supply voltage phase angle at the previous shut-off stored in the storage means, and when that timing is reached Wherein the power cycle by turning on the switching element. Thereby, power cycle. Always performed in time to reduce the inrush current "It is disclosed.

  However, the method described in Patent Document 2 does not specifically show the method for calculating the residual magnetic flux, as described in Patent Document 1, and has a problem in terms of feasibility. In addition, “a switching element that is turned off when the power is shut off is connected to the primary power circuit of the transformer.” Since “low voltage single-phase transformer” is targeted, Large transformers are not covered. This can be inferred from the limitation of the specifications of the switching elements connected on the primary side power supply circuit and the difficulty of handling such as installation and maintenance for practical use. It is presumed that the material is used.

  In addition, the inrush current prevention circuit described in Patent Document 3 includes a power-on control circuit inserted in an AC power line that supplies power to a power input transformer (single phase), a power-on / off detection circuit, a phase detection circuit, and a phase This is a circuit that prevents an inrush current by a closing control circuit and a comparison circuit that operates the switch when the inrush current is not generated by the memory circuit. However, the calculation method of the residual magnetic flux is not specifically shown, and a transformer having a high voltage or a large capacity is not an application target. In addition, Patent Document 4 describes a device that suppresses the magnetizing inrush current by phase angle control, and is a Scott connection, Woodbridge connection transformer, or modification of a transformer that converts a three-phase alternating current into a single-phase alternating current. The control target is a woodbridge transformer. In this device, the suppression target is the single-phase AC side, and there is a configuration in which there are circuit breakers in each of the M phase and the T phase. However, this patent document does not specifically describe a method of calculating the residual magnetic flux.

Japanese Patent No. 5343118 JP-A-10-164754 Japanese Patent Laid-Open No. 57-46416 Japanese Patent No. 5472920

  As described above, there is no prior art document in which the calculation method of the residual magnetic flux is specifically stated for the magnetizing inrush current suppression device intended for application to a single-phase transformer, and the mechanical structure is not. However, there are only circuit breakers with input resistors that require regular maintenance and renewal. In addition, for the purpose of application to a single-phase transformer, due to the nature of the single-phase voltage, there are two phase angles determined from the system voltage when the breaker “ON” signal is received, so that the current phase There is a possibility of misjudging the corner determination. In addition, when the voltage contains harmonics, there is a problem that the accuracy of the current phase angle calculation is lowered. Furthermore, in the case of a single-phase voltage, there is a possibility that the determination of the circuit breaker closing operation time may be erroneously determined due to the influence of noise due to the nature of the single phase voltage. Therefore, the three-phase transformer technology cannot be directly applied to the single-phase technology.

  The present invention has been made in consideration of such circumstances, and it is possible to clearly realize a method for calculating a residual magnetic flux and specifically realize suppression of excitation inrush current of a single-phase transformer. Provided is a magnetizing inrush current suppressing device capable of accurately calculating a current phase angle and accurately determining a circuit breaker operation time even if a phase voltage includes noise and harmonics. For the purpose.

  In order to solve the above problems, the magnetizing inrush current suppressing device of the present invention suppresses the magnetizing inrush current that occurs when a circuit breaker that opens and closes the connection between the single-phase AC voltage power supply system and the single-phase transformer is turned on. A magnetizing inrush current suppressing device, wherein the transformer voltage measuring unit measures the transformer voltage that is the single-phase AC voltage of the first voltage detector installed on the single-phase transformer side of the circuit breaker; A system voltage measuring unit that measures the system voltage that is the single-phase AC voltage of the second voltage detector installed on the system power source side of the circuit breaker, and the transformer measured by the transformer voltage measuring unit A steady magnetic flux calculation unit that calculates a steady magnetic flux inside the iron core of the single-phase transformer based on a transformer voltage, or a timing at which an instantaneous value of the transformer voltage measured by the transformer voltage measurement unit converges to a zero value or Calculated by the steady magnetic flux calculator An effective interruption timing calculation unit that calculates a timing at which the value of the steady magnetic flux reaches a certain value as an effective interruption timing, and the value of the steady magnetic flux calculated by the steady magnetic flux calculation unit at the effective interruption timing as an effective residual magnetic flux An effective residual magnetic flux calculating section for calculating, and making the applied phase angle equal to the polarity of the effective residual magnetic flux calculated by the effective residual magnetic flux calculating section and the polarity of the initial exciting magnetic flux when the circuit breaker is turned on A current phase angle calculation unit that calculates a current phase angle from the system voltage measured by the system voltage measurement unit, the current phase obtained by the current phase angle calculation unit; A closing command output that outputs a closing command to the circuit breaker so that the circuit breaker is turned on at the closing phase angle calculated by the closing phase angle calculation unit according to an angle. Characterized in that it comprises a.

  With the above configuration, it is possible to clearly realize the method of calculating the residual magnetic flux that is essential for suppressing the magnetizing inrush current of the single phase transformer, and to specifically realize the magnetizing inrush current suppression of the single phase transformer. A practical excitation inrush current suppressing device can be obtained.

  In the excitation inrush current suppression device of the present invention, the closing phase angle calculation unit includes the value of the effective residual magnetic flux calculated by the effective residual magnetic flux calculation unit and the value of the initial excitation magnetic flux when the circuit breaker is turned on. The input phase angle can be calculated so that.

  With the above-described configuration of the input phase angle calculation unit, it is possible to suppress a decrease in the excitation rush current suppression rate due to the range in which the difference between the residual magnetic flux and the initial excitation magnetic flux is large.

  In the excitation inrush current suppression device of the present invention, the closing phase angle calculation unit includes the value of the effective residual magnetic flux calculated by the effective residual magnetic flux calculation unit and the value of the initial excitation magnetic flux when the circuit breaker is turned on. The closing phase angle is selected so that the excitation start direction of the magnetic flux generated starting from the effective residual magnetic flux decreases in absolute value among the two solutions of the closing phase angle that coincide with Can do.

  By making the closing phase angle calculation unit as described above, it is possible to prevent the accuracy from being lowered when the variation is larger than the value considering the circuit breaker closing operation time.

  In the magnetizing inrush current suppression device of the present invention, the current phase angle calculation unit calculates an instantaneous value of the system voltage when the circuit breaker receives an “ON” signal, and the instantaneous value and the instantaneous value before and after the instantaneous value are calculated. The current phase angle may be calculated from the system voltage at the timing.

  By configuring the current phase angle calculation unit as described above, even if there are two solutions for the phase angle obtained from the system voltage at the time of receiving the “ON” signal of the circuit breaker, erroneous determination regarding the determination of the current phase angle is prevented. can do.

  In the excitation inrush current suppression device of the present invention, the current phase angle calculation unit generates a pseudo three-phase voltage from the system voltage, and an instantaneous value of the pseudo three-phase voltage when the circuit breaker receives an “on” signal. The current phase angle can be calculated from

  By configuring the current phase angle calculation unit as described above, it is possible to accurately calculate the current phase angle even when the single-phase voltage includes harmonics.

  In the magnetizing inrush current suppression device of the present invention, the timing at which the closing command is output from the closing command output unit is a closing command output time point, and the absolute value of the transformer voltage measured by the transformer voltage measuring unit is Starting from the first timing that exceeds the closing judgment threshold continuously for an arbitrary period, the breaker is determined from the closing command output time and the transformer voltage generating time when the starting point is the voltage generating time It can be set as the structure provided with the circuit breaker closing operation time calculation part which calculates | requires closing operation time.

  By including the circuit breaker closing operation time calculation unit having the above-described configuration, it is possible to prevent an erroneous determination regarding the determination of the circuit breaker closing operation time even if there is an external factor such as generation of noise.

  According to the present invention, the method of calculating the residual magnetic flux can suppress the inrush current of the single-phase transformer, and even if the single-phase voltage includes noise and harmonics, the current phase angle It is possible to realize a magnetizing inrush current suppressing device capable of accurately calculating and determining the circuit breaker closing operation time.

It is a figure which shows the structure of the electric power system to which the magnetizing inrush current suppression apparatus which concerns on embodiment of this invention was applied. It is a figure showing the aspect of the magnetic flux of the single phase transformer which calculated the transformer voltage just before and immediately after the single phase transformer was disconnected from the system power supply, and the transformer voltage by time integration. It is a figure which shows the making-up phase angle of the range which can suppress excitation inrush current. It is a figure which shows the structure of the making phase angle calculation part which concerns on 1st embodiment about a making phase angle calculation part. It is a figure which shows the processing content at the time of charge phase angle calculation. It is a figure which shows the structure of the making phase angle calculation part which concerns on 2nd embodiment about a making phase angle calculation part. It is a figure which shows the aspect of the magnetic flux at the time of supplying with an injection | pouring phase angle. It is a figure which shows the aspect of the magnetic flux at the time of supplying with an injection | pouring phase angle. It is a figure which shows the making operation time until a transformer voltage generate | occur | produces from the signal which output the making command by the making command output part. It is a figure which shows the flow from calculation of the present phase angle at the time of circuit breaker "on" signal reception to control of a circuit breaker with a making phase angle. It is a figure which shows the structure of the current phase angle calculation part in 1st embodiment about a current phase angle calculation part. It is explanatory drawing at the time of calculating the present phase angle of the present system voltage when the system voltage is received at 270 ° <θ ≦ 90 ° and when it is received at 90 ° <θ ≦ 270 °. It is a figure which shows the structure of the present phase angle calculation part in 2nd embodiment about a present phase angle calculation part. It is explanatory drawing at the time of producing | generating a pseudo | simulation three-phase voltage from a system voltage, when a system voltage is a waveform containing a harmonic. It is a figure which shows the relationship between the value which sampled the value of the transformer voltage before and behind a transformer electric power supply by a fixed sampling interval, and an input determination threshold value. It is a figure which shows the time from a charging instruction output time to a transformer voltage generation time, and the change of a transformer voltage. It is a figure which shows the processing flow of the magnetizing inrush current suppression apparatus which concerns on embodiment of this invention. It is a figure which shows the processing flow in 1st embodiment about an injection | pouring phase angle calculation part. It is a figure which shows the processing flow in 2nd embodiment about an injection | pouring phase angle calculation part. It is a figure which shows the processing flow in 1st embodiment about a present phase angle calculation part. It is a figure which shows the processing flow in 2nd embodiment about a present phase angle calculation part. It is a figure which shows the processing flow in embodiment about the circuit breaker insertion operation time calculation part.

Below, the magnetizing inrush current suppression apparatus of this invention is demonstrated based on the embodiment.
A magnetizing inrush current suppression device 30 according to an embodiment of the present invention will be described with reference to FIGS. 1, 2, and 3.

  FIG. 1 is a diagram illustrating a configuration of an electric power system to which an inrush current suppression device 30 according to an embodiment of the present invention is applied. FIG. 17 is a diagram showing a processing flow of the present embodiment. In the following description, the processing steps in FIG.

  The magnetizing inrush current suppressing device 30 includes a transformer voltage measuring unit 1, a steady magnetic flux calculating unit 2, an effective breaking timing calculating unit 3, an effective residual magnetic flux calculating unit 4, a closing phase angle calculating unit 5, and a system voltage measurement. A unit 6, a current phase angle calculation unit 7, a closing command output unit 8, and a circuit breaker closing operation time calculation unit 9 are provided. The input phase angle calculation unit 5 includes a first input phase angle calculation unit 5a and a second input phase angle calculation unit 5b.

  The system power supply 17 is a system in which an arbitrary single-phase power supply is drawn from a three-phase power supply supplied by an electric power company, or a system in which a single-phase power supply is drawn from a single-phase power supply system in the facility.

  The single-phase transformer 11 has the system power supply 17 side as the primary side and the opposite side as the secondary side. The single-phase transformer 11 converts the single-phase voltage supplied from the system power supply 17 into a voltage value and outputs it to the secondary side.

  The circuit breaker 12 is provided between the system power supply 17 and the single-phase transformer 11. When the system power supply 17 is charged, the single-phase transformer 11 is powered on by the system power supply 17 by turning on the circuit breaker 12. The single-phase transformer 11 is disconnected from the system power supply 17 by opening the circuit breaker 12.

  A voltage detector 14 or a voltage detector 15 that is a first voltage detector installed on the single-phase transformer 11 side of the circuit breaker 12 is a measuring device for measuring the voltage on the single-phase transformer 11 side. The voltage detector 16 that is the second voltage detector installed on the system power supply 17 side of the circuit breaker 12 is a measuring device for measuring the voltage on the system power supply 17 side. For example, there is an instrument transformer (VT). The voltage detector 14 or the voltage detector 15 and the voltage detector 16 measure respective voltages. The voltage detector 14 or the voltage detector 15 and the voltage detector 16 output the detected value as a detection signal to the excitation inrush current suppression device 30.

  The magnetizing inrush current suppressing device 30 outputs a closing command to the main contact of the circuit breaker 12 based on information obtained from the detection signals received from the voltage detector 14 or each of the voltage detector 15 and the voltage detector 16. . Thereby, the circuit breaker 12 is turned on.

  The transformer voltage measuring unit 1 measures the instantaneous value, polarity and waveform of the transformer voltage (V1 (t)) on the secondary side of the circuit breaker 12 based on the signals obtained from the voltage detector 14 and the voltage detector 15. To do.

  FIG. 2 shows a single unit of voltage calculated by time-integrating the transformer voltage (V1 (t)) immediately before and immediately after the single-phase transformer 11 is disconnected from the system power supply 17 and the transformer voltage (V1 (t)). It represents the aspect of the magnetic flux (Φ (t)) of the phase transformer 11.

(Steps 1 and 2)
When the steady magnetic flux calculation unit 2 detects the “cut” signal of the circuit breaker 12, the steady magnetic flux calculation unit 2 integrates the transformer voltage (V 1 (t)) measured by the transformer voltage measurement unit 1 and magnetic flux in the iron core of the transformer 11. (Φ (t)) is calculated.

  Here, the relationship between the transformer voltage (V1 (t)) and the magnetic flux (Φ (t)) is the relationship between the equations (1) and (2).

  V1 (t) = Vmcos (t) (1)

  Φ (t) = ∫V1 (t) dt = Φmsin (t) (2)

(Step 3)
The effective interruption timing calculation unit 3 is a timing at which the instantaneous value of the transformer voltage (V1 (t)) measured by the transformer voltage measurement unit 1 when the circuit breaker 12 is open converges to a zero value or a steady magnetic flux calculation unit 2 The timing at which the magnetic flux (Φ (t)) calculated by (1) converges to a constant value is calculated as the effective cutoff timing (t1).
If the instantaneous value of the transformer voltage (V1 (t)) measured by the transformer voltage measuring unit 1 when the circuit breaker 12 is open does not converge to zero due to induction, an arbitrary threshold value is set. And the structure which calculates the timing when the instantaneous value of the transformer voltage (V1 (t)) converged to the zero value may be calculated by substituting the value which becomes below the threshold value with the zero value.

(Step 4)
The effective residual magnetic flux calculation unit 4 uses the magnetic flux (Φ (t1)) at the effective interruption timing (t1) calculated by the effective interruption timing calculation unit 3 among the magnetic flux (Φ (t)) calculated by the steady magnetic flux calculation unit 2. Calculated as the effective residual magnetic flux (Φr).

  The closing phase angle calculation unit 5 makes the closing phase angle (θclose) so that the polarity of the effective residual magnetic flux (Φr) calculated by the effective residual magnetic flux calculation unit 4 matches the polarity of the initial excitation magnetic flux when the circuit breaker 12 is turned on. ) Is calculated.

  In particular, the making phase angle calculation unit 5 according to the present embodiment includes a first making phase angle calculation unit 5a and a second making phase angle calculation unit 5b, and their functions will be described below.

(Steps 7 and 8)
The first closing phase angle calculator 5a calculates the closing phase angle (θclose) so that the range of 0 ° <θclose <180 ° is obtained when the polarity of the effective residual magnetic flux (Φr) is positive.
FIG. 3A illustrates the input phase angle (θclose) within a range in which the magnetizing inrush current can be suppressed. Here, it is assumed that the effective residual magnetic flux (Φr) is 0.5 pu, but it is also established at an arbitrary value (0 <Φr ≦ 1).

  Here, “pu” is a unit method (per unit method), and the peak values of voltage and magnetic flux are represented by 1 pu. The same applies to the following description.

(Steps 7 and 9)
The second closing phase angle calculation unit 5b calculates the closing phase angle (θclose) so that the range of 180 ° <θclose <360 ° is obtained when the polarity of the effective residual magnetic flux (Φr) is negative.
FIG. 3B illustrates the input phase angle (θclose) within a range in which the magnetizing inrush current can be suppressed. Here, it is assumed that the effective residual magnetic flux (Φr) is −0.5 pu, but any arbitrary This is also true for the value (−1 ≦ Φr <0).

(Steps 5 and 6)
Further, when the effective residual magnetic flux (Φr) is zero, the closing phase angle (θclose) is calculated from the angles in the entire range of one cycle.

  The system voltage measurement unit 6 measures the instantaneous value, polarity, and waveform of the system voltage (V2 (t)) on the system power supply 17 side of the circuit breaker 12 by a signal obtained from the voltage detector 16.

(Steps 10 and 11)
When the current phase angle calculation unit 7 detects the “ON” signal of the circuit breaker 12, the system voltage (V2 (t)) at the moment of detection is determined by the system voltage (V2 (t)) measured by the system voltage measurement unit 6. The current phase angle (θ1) is calculated.

(Steps 12 and 13)
The closing command output unit 8 issues a closing command to the circuit breaker 12 based on the current phase angle (θ1) calculated by the current phase angle calculating unit 7 and the closing phase angle (θclose) calculated by the closing phase angle calculating unit 6. Is output and the circuit breaker closing control is completed. Details of this processing will be described later. The function of the circuit breaker closing operation time calculation unit 9 will be described in detail later.

  Although the voltage drop amount calculation unit 10 is not essential in the present invention, the voltage drop amount calculation unit 10 was measured by the system voltage measurement unit 6 when evaluating the suppression rate of the voltage drop amount by providing the voltage drop amount calculation unit 10. The voltage drop when the circuit breaker 12 is turned on can be calculated from the system voltage.

  In addition, the closing phase angle actual value calculation unit 20 is not essential in the present invention, but by providing the closing phase angle actual value calculation unit 20, when evaluating the accuracy of the actual value with respect to the closing command value, the circuit breaker 12. The phase of the system voltage (V2 (tclose)) measured by the system voltage measurement unit 6 at the transformer voltage generation time (tclose) measured by the transformer voltage measurement unit 1 at the time of charging may be calculated. .

  As described above, the magnetizing inrush current suppressing device 30 according to the present embodiment generates the effective residual magnetic flux (Φr) with respect to the residual magnetic flux in the iron core of the single-phase transformer 11 when the circuit breaker 12 is opened, by the effective interruption timing (t1). The closing phase angle (θclose) when the breaker 12 is turned on is calculated based on the effective residual magnetic flux (Φr). And the magnetizing inrush current suppression apparatus 30 can suppress the magnetizing inrush current by controlling the circuit breaker 12 by the closing phase angle (θclose).

  When the above method is compared with the method in the prior art document for a three-phase transformer, in the case of a three-phase transformer, the range in which each phase of the residual magnetic flux and the initial excitation magnetic flux can maintain the same polarity is 60. In the present invention, the range is 180 degrees, which is advantageous in that control is possible in a wider range of angles than in the prior art. Also, the hardware configuration and software configuration can be simplified as compared with the case of a three-phase transformer.

Next, a first embodiment of the input phase angle calculation unit 5 will be described.
The closing phase angle calculation unit 5 according to the present embodiment matches the value of the effective residual magnetic flux (Φr) calculated by the effective residual magnetic flux calculation unit 4 with the value of the initial excitation magnetic flux when the next breaker is turned on. The input phase angle (θclose) is calculated.

  FIG. 4 is a diagram illustrating a configuration of the making phase angle calculation unit according to the first embodiment of the making phase angle calculation unit 5. FIG. 18 is a diagram showing a processing flow of this embodiment, and a portion in a frame in FIG. 18 is a characteristic portion in this embodiment. In the following description, the processing steps in FIG. 18 are also shown. FIG. 5 illustrates the processing contents when calculating the input phase angle.

(Steps 7 and 8)
When the polarity of the effective residual magnetic flux (Φr) is positive, the third input phase angle calculation unit 5c shown in FIG. 4 has an equation so that the value of the effective residual magnetic flux (Φr) matches the value of the initial excitation magnetic flux. The input phase angle (θclose) is calculated by (3).

θclose = sin ⁻¹ (Φr) = α, 180−α
(However, Φr> 0, α: 0 ° <α <180 °) (3)

  FIG. 5A illustrates the input phase angle (θclose) where the value of the effective residual magnetic flux (Φr) and the value of the initial excitation magnetic flux coincide with each other when the polarity of the effective residual magnetic flux (Φr) is positive. There are two solutions for the input phase angle (θclose). Here, it is assumed that the effective residual magnetic flux (Φr) is 0.5 pu, but it is also established at an arbitrary value (0 <Φr ≦ 1).

(Steps 7 and 9)
The fourth input phase angle calculation unit 5d shown in FIG. 4 uses an equation so that the value of the effective residual magnetic flux (Φr) matches the value of the initial excitation magnetic flux when the polarity of the effective residual magnetic flux (Φr) is negative. The input phase angle (θclose) is calculated by (4).

θclose = sin ⁻¹ (Φr) = β, 180−β
(However, Φr <0, β: 180 ° <β <360 °) (4)

  FIG. 5B illustrates the input phase angle (θclose) at which the value of the effective residual magnetic flux (Φr) matches the value of the initial excitation magnetic flux when the polarity of the effective residual magnetic flux (Φr) is negative. There are two solutions for the input phase angle (θclose). Here, it is assumed that the effective residual magnetic flux (Φr) is −0.5 pu, but it is also established at an arbitrary value (−1 ≦ Φr <0).

(Steps 5 and 6)
Further, the processing for calculating the closing phase angle (θclose) when the effective residual magnetic flux (Φr) is zero is determined as two solutions of 0 ° or 180 ° according to the equation (5).

θclose = sin ⁻¹ (Φr = 0) = 0 °, 180 ° (5)

  According to the first embodiment of the input phase angle calculation unit 5 described above, it is possible to suppress a decrease in the excitation inrush current suppression rate due to the range in which the difference between the residual magnetic flux and the initial excitation magnetic flux is large. it can.

Next, a second embodiment of the input phase angle calculation unit 5 will be described.
The closing phase angle calculation unit 5 according to the present embodiment has a closing phase in which the value of the effective residual magnetic flux (Φr) calculated by the effective residual magnetic flux calculation unit 4 matches the value of the initial excitation magnetic flux when the circuit breaker 12 is turned on. Among the two solutions of the angle (θclose), the input phase angle (θclose) is selected in such a direction that the excitation start direction of the magnetic flux generated from the effective residual magnetic flux (Φr) decreases in absolute value.

  FIG. 6 is a diagram illustrating a configuration of the making phase angle calculation unit 5 according to the second embodiment of the making phase angle calculation unit 5. FIG. 19 is a diagram showing a processing flow of the present embodiment, and a portion in a frame in FIG. 19 is a characteristic portion in the present embodiment. In the following description, the processing steps in FIG. 19 are also shown. FIGS. 7 and 8 illustrate the state of the magnetic flux when being applied at the closing phase angle (θclose).

  7 and 8 show the hysteresis characteristics of the transformer with the vertical axis representing the magnetic flux and the horizontal axis representing the current, indicating that the current rapidly increases when the magnetic flux reaches the saturation region. Yes.

(Steps 7, 8, 8a)
The fifth closing phase angle calculator 5e shown in FIG. 6 has an effective residual magnetic flux (Φr) out of two solutions of the closing phase angle (θclose) calculated from the third closing phase angle calculator 5c by the equation (6). ) Is selected as the starting phase angle (θclose) in the direction in which the excitation start direction of the generated magnetic flux decreases in absolute value.

θclose = sin ⁻¹ (Φr) = α, 180−α
(However, Φr> 0, α: 0 ° <α <180 °) (6)

  FIG. 7A illustrates the appearance of the magnetic flux when being applied at the closing phase angle (θclose) selected in the present embodiment, out of the two closing phase angles (θclose) obtained by Equation (6). FIG. 7B illustrates the state of the magnetic flux when being applied at a closing phase angle (θclose) that is not selected in the present embodiment.

(Step 6)
FIG. 9 shows the closing operation time from when the closing command output unit 8 outputs the closing command to the time when the transformer voltage (V2 (t)) is generated. The circuit breaker is actually operated at the closing phase angle (θclose). 9 when there is a variation in the operation time until the transformer voltage (V2 (t)) is generated from the signal output from the input command output unit 8 shown in FIG. Variation also occurs in the input phase angle (θclose) between the measured value and the actually measured value.

  Thus, in selecting the two solutions of the closing phase angle (θclose), considering that there are variations in the closing phase angle of the command value and the actual measurement value due to variations in the operation time of the circuit breaker 12, The closing phase angle (θclose) is selected so as to move away from the point where the current increases rapidly.

  That is, when the polarity of the effective residual magnetic flux (Φr) is positive, “180−α” is selected from the two solutions of θclose in Expression (6). Here, it is assumed that the effective residual magnetic flux (Φr) is 0.9 pu, but it is also established at an arbitrary value (0 <Φr ≦ 1).

(Steps 7, 9, 9a)
The sixth closing phase angle calculation unit 5f shown in FIG. 6 has an effective residual magnetic flux (Φr) out of two solutions of the closing phase angle (θclose) calculated from the fourth closing phase angle calculation unit 5d by the equation (7). ) Is selected as the starting phase angle (θclose) in the direction in which the excitation start direction of the generated magnetic flux decreases in absolute value.

θclose = sin ⁻¹ (Φr) = β, 180−β
(However, Φr <0, β: 180 ° <β <360 °) (7)

  FIG. 8A illustrates the state of the magnetic flux when being applied at the closing phase angle (θclose) selected in the present embodiment among the two closing phase angles (θclose). ) Illustrates the state of the magnetic flux when being applied at an applied phase angle (θclose) that is not selected in the present embodiment.

(Step 9a)
When the breaker 12 is actually turned on at the closing phase angle (θclose), the transformer voltage (V2 (t)) is generated from the signal output from the closing command output unit 8 shown in FIG. Since there is a variation in the making operation time, there is also a variation in the making command value and the making phase angle (θclose) of the actual measurement value.

  Thus, in selecting the two solutions of the closing phase angle (θclose), considering that there are variations in the closing phase angle of the command value and the actual measurement value due to variations in the operation time of the circuit breaker 12, The closing phase angle (θclose) is selected so as to move away from the point where the current increases rapidly.

  That is, when the polarity of the effective residual magnetic flux (Φr) is negative, “β” is selected from the two solutions of θclose in Expression (7). Here, it is assumed that the effective residual magnetic flux (Φr) is −0.9 pu, but it is also established at an arbitrary value (−1 ≦ Φr <0).

(Steps 5 and 6)
Further, the processing for calculating the closing phase angle (θclose) when the effective residual magnetic flux (Φr) is zero is determined as two solutions of 0 ° or 180 ° from the equation (8). Either of these may be selected.

θclose = sin ⁻¹ (Φr = 0) = 0 °, 180 ° (8)

  According to the second embodiment of the making phase angle calculation unit 5 described above, in actual application, the circuit breaker 12 has a variation in making operation time, and the making command angle and the making phase angle of the measured value vary. Considering the fact that the input phase angle (θclose) is selected, it is possible to carry out with higher accuracy.

Next, a first embodiment of the current phase angle calculation unit will be described.
The current phase angle (θ1) at the time of receiving the “ON” signal of the circuit breaker 12 calculated by the current phase angle calculation unit 7 is essential when controlling the circuit breaker 12 with the input phase angle (θclose).

  FIG. 10 is a diagram showing a flow from the calculation of the current phase angle (θ1) at the time of receiving the breaker 12 “on” signal to the control of the breaker 12 with the closing phase angle (θclose) in the present embodiment.

  In order to control the circuit breaker 12 at the closing phase angle (θclose), it is necessary to consider the closing operation time after the closing command is output as shown in FIG. The making command output point is obtained by adding the making phase angle (θclose) calculated by the making phase angle calculating unit 5 and the making operation time.

  The closing command delay time is obtained from the closing command output point and the current phase angle (θ1) when the breaker 12 “ON” signal is received.

  To summarize the above control flow, the circuit breaker 12 takes into account by outputting a closing command at a closing command output point after a closing command delay time from the current phase angle (θ1) at which the closing signal is received. After the closing operation time, it is turned on at the closing phase angle (θclose), the circuit breaker 12 is turned off and the circuit breaker 12 is turned on, and the control is completed.

  FIG. 11 shows the configuration of the current phase angle calculation unit in the first embodiment for the current phase angle calculation unit. FIG. 20 is a diagram showing a processing flow of the present embodiment, and a portion in a frame in FIG. 20 is a characteristic portion in the present embodiment. In the following description, the processing steps in FIG. 20 are also shown.

  FIG. 11 shows that the current phase angle calculation unit 7 shown in FIG. 1 includes a current system voltage calculation unit 7a and a current phase angle calculation unit 7b in the present embodiment. The current system voltage calculation unit 7a calculates an instantaneous value of the system voltage (V2 (t1)) when the circuit breaker 12 “ON” signal is received, and the current phase angle calculation unit 7b calculates the system voltage (V2 (t1) )) And the current phase angle (θ1) is calculated from the system voltage before and after the instantaneous value.

(Steps 10 and 11a)
The present system voltage calculation unit 7a according to the present embodiment calculates the system voltage (V2 (t1)) measured by the system voltage measurement unit 6 when the circuit breaker 12 “ON” signal is received.

(Steps 11b, 11c, 11d)
The current phase angle calculator 7b calculates the system voltage (V2 (t1)) as a reference point, and calculates the instantaneous value of the system voltage (V2 (t1)) and the system voltage instantaneous value before and after the system voltage (V2 (t1)). The current phase angle (θ1) is calculated by comparing the size.

  The system voltage (V2 (t)) can take a range of 0 ° ≦ θ <360 ° depending on the timing of receiving the circuit breaker 12 “ON” signal. FIG. 12 shows a case where the circuit breaker 12 “ON” signal is received when the system voltage (V2 (t)) is in the range of 270 ° <θ ≦ 90 °, and the circuit breaker in the range of 90 ° <θ ≦ 270 °. It is explanatory drawing at the time of calculating the present phase angle ((theta) 1) of the present system voltage (V2 (t1)) at the time of receiving 12 "on" signal.

  There are two current phase angles (θ1) from the system voltage (V2 (t1)) measured by the system voltage measurement unit 6 when the circuit breaker 12 “ON” signal is received, according to Equation (9).

θ1 = sin ⁻¹ (V2 (t1)) = ε, 180−ε
(Ε: 0 ° ≦ ε <360 °) Equation (9)

(Steps 11c and 11d)
In FIG. 12, the current phase angle (θ1) is calculated using the system voltage (V2 (t1)) measured by the system voltage measuring unit 6 when the circuit breaker 12 “ON” signal is received as a reference point. In the case of V2 (t1-1)) ≦ V2 (t1 + 1) with respect to the value immediately before (V2 (t1-1)) and the value immediately after the reference point (V2 (t1 + 1)), In the equation (9), θ1 = ε is selected. If V2 (t1-1)> V2 (t1 + 1), θ1 = 180−ε is selected.

As described above, the current phase angle (θ1) is calculated using the system voltage (V2 (t1)) as a reference point, and is one before the system voltage (V2 (t1)) and the system voltage (V2 (t1)). The current phase angle (θ1) is calculated by comparing the value of the current value or the next value with the instantaneous value of the system voltage.
In the comparison of the values before and after the system voltage (V2 (t1)) serving as a reference when calculating the current phase angle (θ1), the number and position of values to be compared can be determined as appropriate.

  In the first embodiment of the current phase angle calculation unit described above, there are two solutions of the system voltage (V2 (t1)) at the time of receiving the circuit breaker 12 “on” signal, and the current phase angle (θ1) necessary for control is present. When it is difficult to determine the current phase angle (θ1), the system voltage (V2 (t1)) is used as a reference point, and the current phase angle (θ1) is calculated based on the magnitude relationship between the preceding and subsequent values. Thereby, even if there are two solutions of the phase angle obtained from the system voltage at the time of receiving the circuit breaker 12 “ON” signal, it is possible to prevent an erroneous determination regarding the determination of the current phase angle.

Next, a second embodiment of the current phase angle calculation unit will be described.
FIG. 13 shows the configuration of the current phase angle calculation unit in the second embodiment for the current phase angle calculation unit. FIG. 21 is a diagram showing a processing flow of the present embodiment, and a portion in a frame in FIG. 21 is a characteristic portion in the present embodiment. In the following description, the processing steps in FIG. 21 are also shown.

  In FIG. 13, the current phase angle calculation unit 7 shown in FIG. 1 includes a pseudo three-phase voltage calculation unit 7c, a current pseudo three-phase voltage calculation unit 7d, and a current phase angle calculation unit 7e in the present embodiment. It has been shown.

(Steps A, 10, 11e, 11f)
The pseudo three-phase voltage calculation unit 7c generates a pseudo three-phase voltage from the system voltage (V2 (t)) measured by the system voltage measurement unit 6, and the current pseudo three-phase voltage calculation unit 7d The instantaneous value of the pseudo three-phase voltage at the time of signal reception is calculated, and the current phase angle calculation unit 7e calculates the current phase angle (θ1) from the instantaneous value of the pseudo three-phase voltage using the pseudo three-phase voltage.

(Step A)
FIG. 14 shows a waveform in which the system voltage (V2 (t)) measured by the system voltage measuring unit 6 includes harmonics, and a pseudo three-phase voltage is generated from the system voltage (V2 (t)). It is explanatory drawing.

(Step A)
For the generation of the other two-phase V3 (θ) and V4 (θ) shown in FIG. 14A, the zero cross point at the rise of the system voltage (V2 (t)) measured by the system voltage measurement unit 6 Is generated for one cycle from the zero cross point by the equations (10) and (11) from the peak value of the previous cycle, and repeatedly generated for each zero cross point.

(Step A)
V3 (θ) = Vmsin (θ + 240 °)
(Θ: 0 ° ≦ θ <360 °) (10)

(Step A)
V4 (θ) = Vmsin (θ + 120 °)
(Θ: 0 ° ≦ θ <360 °) (11)

(Step A)
As for the generation of V5 (θ) shown in FIG. 14B, the system voltage (V2 (t)) is simulated and generated from Expression (10) and Expression (11) using Expression (12).

(Step A)
V5 (θ) = Vmsin (θ)
(Θ: 0 ° ≦ θ <360 °) (12)

(Steps 10, 11e, 11f)
When the system voltage (V2 (t)) measured by the system voltage measurement unit 6 includes harmonics, if the system voltage (V2 (t)) is used for the calculation of the current phase angle (θ1), it is erroneously calculated. Therefore, as a countermeasure, the current phase angle (θ1) of the pseudo three-phase voltage when the circuit breaker 12 “input” signal is received is calculated by using the pseudo three-phase voltage according to the equation (13).

（θ１：０°≦θ１＜３６０°） …式（１３） (Step 11f)

(Θ1: 0 ° ≦ θ1 <360 °) (13)

  Regarding the calculation of the current phase angle (θ1), the system voltage (V5 (t1)) at the time of receiving the circuit breaker 12 “on” signal is calculated as a reference point, and the system voltage before and after the system voltage (V5 (t1)) is calculated. The current phase angle (θ1) may be calculated by comparing the magnitude with the instantaneous value. Further, in the comparison of the values before and after the system voltage (V5 (t1)), which is the reference when calculating the current phase angle (θ1), the number and position of the values to be compared can be determined as appropriate.

  The current phase angle (θ1) is calculated using the system voltage (V5 (t1)) at the time of receiving the circuit breaker 12 “on” signal as a reference point, and the system voltage (V5 (t1)) and system voltage ( The current phase angle (θ1) may be calculated by comparing the magnitude of the previous value of V5 (t1)) or the instantaneous value of the system voltage with the next value. Also in this case, in the comparison of the values before and after the system voltage (V5 (t1)) that is the reference when calculating the current phase angle (θ1), the number and position of the values to be compared can be determined as appropriate.

In the second embodiment described above for the current phase angle calculation unit, the current phase angle calculated by the current phase angle calculation unit 7e using the pseudo three-phase voltage calculated by the pseudo three-phase voltage calculation unit 7c ( θ1) is calculated.
In the prior art document, when calculating the current phase angle in the magnetizing inrush current suppression device of the three-phase transformer, the current phase angle is calculated from the instantaneous value of the measured three-phase voltage and includes harmonic components. However, in the case of a single-phase transformer, if the same processing is performed, if the harmonic component is included, the current phase angle is calculated due to this effect. It can happen that the accuracy of the process is reduced. However, the current phase angle can be accurately calculated by calculating the current phase angle by the method of the present embodiment, instead of using the single phase voltage as it is for the current phase angle calculation.

Next, an embodiment of the circuit breaker closing operation time calculation unit will be described.
In the present embodiment, the circuit breaker closing operation time calculation unit 9 includes a transformer voltage determination unit 9a and a transformer voltage continuity determination unit 9b as shown in FIG. FIG. 22 is a diagram showing a processing flow of the present embodiment, and a portion in a frame in FIG. 22 is a characteristic portion in the present embodiment. In the following description, the processing steps in FIG. 22 are also shown.

(Steps X1, X2, X3, X4)
The circuit breaker closing operation time calculating unit 9 is a transformer voltage (V1 (t)) measured by the transformer voltage measuring unit 1 from a closing command output time point when the closing command is output by the closing command output unit 8. The time until the transformer voltage generation time, which is the starting point when the absolute value of exceeds the input determination threshold value continuously for an arbitrary period, is calculated.

  FIG. 15 illustrates the relationship between the value obtained by sampling the transformer voltage (V1 (t)) before and after the transformer is applied at a constant sampling interval (ts) and the input determination threshold value ± α. is there.

  As shown in FIG. 15, before the transformer is charged, the transformer voltage exceeds the input determination threshold value due to external factors such as noise generation (α <V1 (t) or V1 (t) <− α ), And after transformer application, the transformer voltage may be lower than the input determination threshold value due to the relationship between the sampling period and the voltage waveform (−α <V1 (t) <α).

(Step X1)
The transformer voltage determination unit 9a may erroneously determine that the transformer voltage is generated when the transformer voltage exceeds the input determination threshold due to an external factor before the transformer is applied, or the transformer after the transformer is applied. In order not to mistakenly judge that the transformer voltage is not present when the voltage falls below the threshold value, the voltage is acquired at a sampling interval of every 3 degrees with respect to the input voltage waveform. The reference point when three points out of the total four sampling voltages of the voltage, the voltage from the reference point to 2 sampling before, and the sampling voltage one point ahead of the reference point exceed the input judgment threshold value ± α It is determined that the transformer voltage is generated in That is, it is determined whether or not the transformer voltage is generated at the reference point by acquiring a plurality of transformer voltages at a constant sampling period and determining whether or not the acquired voltages at the plurality of points exceed the input determination threshold value.

  FIG. 16 illustrates the change from the time when the input command is output (tcx) to the time when the transformer voltage is generated (tclose) and the transformer voltage. In FIG. 16, (a) input command output, (b) noise generation, (c) transformer voltage presence / absence, (d) continuity evaluation, (e) transformer voltage presence / absence (after continuity evaluation) are shown. .

  In the case of noise generation, (a) after the input command is output, (b) the time when the transformer voltage is generated when noise is generated is (1) the temporary transformer voltage generation time (tclose0). During the transformer voltage continuity determination time β, which represents the time when the continuity evaluation is 1, since (c) the transformer voltage indicated by the presence or absence of the transformer voltage is not generated, it is not calculated as the transformer voltage generation time point, (E) Transformer voltage presence / absence (after continuity evaluation) remains zero.

  If it is not noise, the time when the transformer voltage is generated is (2) the temporary transformer voltage generation time (tclose0), and (d) the transformer voltage continuity determination indicates the time when the continuity evaluation is 1. (C) When a transformer voltage indicated by the presence or absence of a transformer voltage is generated during time β, (2) the temporary transformer voltage generation time (tclose0) is set as the transformer voltage generation time (tclose), and (e) It shows that the transformer voltage presence / absence (after continuity evaluation) is set to 1.

(Step X2)
The transformer voltage continuity determination unit 9b obtains a temporary transformer voltage generation time point (tclose0) from the presence / absence of voltage generation determined by the transformer voltage determination unit 9a, and the transformer voltage generation time point (tclose0) When the voltage continuity determination time β is one cycle of the voltage waveform, and all the determination results of the transformer voltage determination unit 9a are the presence of the transformer voltage, the temporary transformer voltage generation time (tclose0) is generated as the transformer voltage. Calculate as the time (tclose).
That is, when it is determined that the transformer voltage has been continuously generated for a certain period of time, the time when it is determined that the transformer voltage has been generated for the first time is calculated as the transformer voltage generation time.

(Step X4)
From the input instruction output time (tcx) and the transformer voltage generation time (tclose), the input operation time (tcb) is calculated by the equation (14).

  tcb = tclose-tcx (14)

  In this way, the timing at which the closing command is output from the closing command output unit 8 is set as the closing command output time point, and the absolute value of the transformer voltage measured by the transformer voltage measuring unit 1 is determined to be continuously input for an arbitrary period. Starting from the first timing that exceeds the threshold, when the starting point is the time when the transformer voltage is generated, the circuit breaker closing operation time can be obtained from the point when the closing command is output and the point when the transformer voltage is generated. This is a function of the operation time calculation unit 9.

  In the above description, the transformer voltage determination unit 9a obtains a voltage at a sampling interval of every 3 degrees with respect to the input voltage waveform, and determines the voltage at the reference point and the voltage from the reference point to 2 sampling before. Of the total four sampling voltages with the sampling voltage one point ahead of the reference point, three points are used as the judgment criterion of the making judgment threshold. However, the sampling period, the making judgment threshold, and the number of samples used for the judgment are It can change suitably, and it can be set as the structure which changes a judgment standard manually or automatically. In addition, the transformer voltage continuity determination unit 9b uses the continuity for one period of the voltage waveform as a determination criterion, but the period used for determination can be changed as appropriate, and the determination criterion can be changed manually or automatically. It can be set as the structure made to do.

  In the prior art for calculating the input operation time for a three-phase transformer, it can be easily judged by looking at the voltage of each of the three phases, and the threshold value used as a judgment criterion can be set high. The possibility of misjudgment is extremely low. However, for single-phase transformers, the situation is different from that for three-phase transformers, and the method for three-phase transformers cannot be applied as it is.

  In the present embodiment described above, the input operation time calculation unit 9 uses the transformer voltage generation time point obtained by the transformer voltage determination unit 9a and the transformer voltage continuity determination unit 9b, so that the occurrence of noise or the like can be avoided. Even if there is a cause, it is possible to prevent an erroneous determination regarding the determination of the circuit breaker closing operation time, and to determine the closing operation time in the single-phase transformer with high accuracy.

  The present invention can suppress the magnetizing inrush current of the single-phase transformer by the method of calculating the residual magnetic flux and calculate the current phase angle even when the single-phase voltage includes noise and harmonics. It can be widely used as a magnetizing inrush current suppressing device capable of accurately determining the circuit breaker closing operation time.

DESCRIPTION OF SYMBOLS 1 Transformer voltage measurement part 2 Steady magnetic flux calculation part 3 Effective interruption | blocking timing calculation part 4 Effective residual magnetic flux calculation part 5 Input phase angle calculation part 5a 1st input phase angle calculation part 5b 2nd input phase angle calculation part 5c 3rd 5d fourth phase angle calculator 5e fifth phase angle calculator 5f sixth phase angle calculator 6 system voltage measurement unit 7 current phase angle calculator 7a current system voltage calculator 7b Current phase angle calculation unit 7c Pseudo three-phase voltage calculation unit 7d Current pseudo three-phase voltage calculation unit 7e Current phase angle calculation unit 8 Input command output unit 9 Breaker input operation time calculation unit 9a Transformer voltage determination unit 9b Transformer voltage Continuity determination unit 10 Voltage drop amount calculation unit 11 Single phase transformer 12 Circuit breaker 14, 15 Voltage detector 16 Voltage detector 17 System power supply 20 Input phase angle actual value calculation unit 30 Excitation current suppression device

Claims (6)

An excitation inrush current suppression device that suppresses an excitation inrush current that occurs when a circuit breaker that opens and closes a connection between a single phase AC voltage power supply system and a single phase transformer is provided,
A transformer voltage measuring unit for measuring a transformer voltage which is the single-phase AC voltage of a first voltage detector installed on the single-phase transformer side of the circuit breaker, and a system power supply side of the circuit breaker A system voltage measuring unit for measuring a system voltage that is the single-phase AC voltage of the second voltage detector,
A steady magnetic flux calculating unit that calculates a steady magnetic flux inside the iron core of the single-phase transformer from the transformer voltage measured by the transformer voltage measuring unit,
The timing at which the instantaneous value of the transformer voltage measured by the transformer voltage measuring unit converges to a zero value or the timing at which the value of the steady magnetic flux calculated by the steady magnetic flux calculating unit reaches a constant value is defined as an effective cutoff timing. It has an effective cutoff timing calculation unit to calculate,
An effective residual magnetic flux calculating unit that calculates the value of the steady magnetic flux calculated by the steady magnetic flux calculating unit at the effective interruption timing as an effective residual magnetic flux;
A closing phase angle calculation unit that calculates a closing phase angle so as to match the polarity of the effective residual magnetic flux calculated by the effective residual magnetic flux calculation unit and the polarity of the initial excitation magnetic flux when the circuit breaker is turned on;
A current phase angle calculation unit that calculates a current phase angle from the system voltage measured by the system voltage measurement unit;
A closing command that outputs a closing command to the circuit breaker so that the circuit breaker is turned on at the closing phase angle calculated by the closing phase angle calculating unit according to the current phase angle obtained by the current phase angle calculating unit. A magnetizing inrush current suppressing device comprising a command output unit.   The closing phase angle calculation unit is configured so that the value of the effective residual magnetic flux calculated by the effective residual magnetic flux calculation unit coincides with the value of the initial excitation magnetic flux when the circuit breaker is turned on. The inrush current suppression device according to claim 1, wherein the inrush current suppression device is calculated.   The closing phase angle calculation unit has two solutions of the closing phase angle at which the value of the effective residual magnetic flux calculated by the effective residual magnetic flux calculation unit matches the value of the initial excitation magnetic flux when the circuit breaker is turned on. 3. The method according to claim 1, wherein an excitation phase direction of a magnetic flux generated with the effective residual magnetic flux as a starting point is selected so that the input phase angle decreases in an absolute value. Inrush current suppression device.   The current phase angle calculation unit calculates an instantaneous value of the system voltage when the circuit breaker receives an “ON” signal, and calculates the current phase angle from the instantaneous value and the system voltage at a timing before and after the instantaneous value. The excitation inrush current suppressing device according to any one of claims 1 to 3, wherein the apparatus is calculated.   The current phase angle calculation unit generates a pseudo three-phase voltage from the system voltage, and calculates the current phase angle from an instantaneous value of the pseudo three-phase voltage when the breaker receives an “ON” signal. The excitation inrush current suppressing device according to claim 1, wherein   The timing at which the closing command is output from the closing command output unit is a closing command output time point, and the absolute value of the transformer voltage measured by the transformer voltage measuring unit is continuously determined for a predetermined period. The breaker closing operation time calculation for obtaining the breaker closing operation time from the closing command output time and the transformer voltage generation time when the starting timing is the time when the transformer voltage is generated. The magnetizing inrush current suppressing device according to claim 1, further comprising a portion.

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