JP2014023303A - Reverse power flow factor determination method and device for power distribution automatic voltage regulator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of determining whether a factor of reverse power flow in a power distribution automatic voltage regulator (an automatic voltage regulator) is in system switching or in that a distributed power supply is connected to a secondary side.SOLUTION: At the reverse power flow, primary and secondary voltages of an automatic voltage regulator are measured at a first measurement timing before a tap of the automatic voltage regulator is switched, at a second measurement timing immediately after the tap switching, and at a third measurement timing slightly delayed from the second measurement timing, respectively. A load state of a system immediately after the voltage adjustment is determined from results of comparison between the primary voltages and between the secondary voltages measured at the second and third measurement timings. The determined load state, results of comparison between the primary voltages and between the secondary voltages measured at the first and third measurement timings, and results of determining whether a voltage adjustment operation is tap-up or tap-down, are verified with preliminarily-prepared determination requirements, and thereby a factor of the reverse power flow is determined.

Description

  In the present invention, when a reverse power flow occurs in the automatic voltage regulator installed in the distribution system, the reverse power flow is caused by switching the system, or on the secondary side of the automatic voltage regulator. The present invention relates to a power reverse power flow cause determination method and apparatus for an automatic voltage regulator for power distribution that determines whether a distributed power source is connected to a system.

  In a power distribution system, a plurality of systems are interconnected in order to balance power supply and demand and to prevent power outages during construction. In recent years, as power generation facilities such as solar power generation facilities and wind power generation facilities have been installed as private power generation facilities, many private power generation facilities have become connected to the distribution system as distributed power sources. Yes.

  In a power distribution system, in order to keep the voltage of each part of the system within a set range, an automatic voltage regulator for power distribution (hereinafter also referred to as SVR) is installed in the system at an appropriate interval, and the voltage of each part of the system is set. Adjustments are made to maintain the setting range. SVR, for example, has a tap on the primary side and the primary and secondary sides are connected to the primary (power supply side) and secondary distribution lines, respectively, and tap switching to switch the adjustment transformer taps And a voltage adjustment operation for maintaining the system voltage (distribution line voltage) within a set range by switching the tap of the adjustment transformer according to the system voltage.

  In this specification, the distribution line on the primary side of the SVR is connected to the power supply substation, the distribution line on the secondary side of the SVR is disconnected from the power supply substation of the other system, and the power flow state is the forward power flow. The voltage adjustment operation (tap switching operation) that switches the tap in the direction that boosts the voltage on the secondary side of the adjustment transformer when it is in a state is called “tap raising” and is the reverse of the tap raising operation. The voltage adjustment operation for switching the tap in the direction is called “tap lowering”.

  The distribution line connected to the primary side of the SVR is connected to the power substation, the distribution line connected to the secondary side of the SVR is disconnected from the power supply substations of other systems, and the power flow in the SVR is When power flow is present, taps are raised when the system voltage falls below the set range, and taps are lowered when the set voltage exceeds the set range, thereby maintaining the voltage of each part of the distribution system within the set range. can do. However, in the power distribution system, the power flow in each SVR is not always in the forward power flow state, and depending on the system state, the power flow in the SVR may be in the reverse power flow state (power from the secondary side to the primary side). May be reversely sent).

  For example, in a distribution system that connects a plurality of systems, the system is switched on the primary side and the secondary side of the SVR, the distribution line on the primary side of the SVR is disconnected from the power substation, and the distribution on the secondary side When the electric wire is connected to a power substation of another system, the power flow in the SVR becomes a reverse power flow state. Moreover, in a distribution system in which a large number of distributed power sources may be linked in addition to a plurality of grids being connected, even if the primary distribution line of the SVR is connected to the power substation, When many distributed power sources are linked to the next side, the power flow in the SVR may be in a reverse power flow state. When a reverse power flow occurs in SVR, correct voltage adjustment cannot be performed and the voltage of each part of the system becomes abnormal, so it is necessary to take some measures.

  In SVR used in a distribution system that links a plurality of systems, system switching is performed in which a primary distribution line is disconnected from a power substation and a secondary distribution line is connected to a power substation of another system. When done, a reverse power flow occurs. In this case, if the tap is raised so that the SVR keeps the secondary system voltage within the set range, the primary system voltage falls below the lower limit of the set range, and the SVR primary side distribution system The voltage drops abnormally. In order to prevent such an abnormal state from occurring, an SVR used in a distribution system that links a plurality of systems is operated by a command station installed at a substation or the like when a system that generates reverse power flow is switched. Is configured to perform an operation of fixing the tap of the adjustment transformer to a predetermined tap. An SVR that performs such an operation will be referred to as a “back feed fixed tap type SVR”. An SVR that does not perform the operation of fixing the tap of the adjustment transformer at the time of system switching will be referred to as a “general type SVR”. In the reverse feed tap fixed type SVR, the first through tap is selected as the fixed tap to be selected at the time of system switching, and then the tap that will boost the primary system voltage during the reverse power flow is selected.

  In a distribution system in which a plurality of systems are linked, if a reverse power flow occurs in the SVR only at the time of system switching, the reverse power tap is used in the SVR by using the above-described reverse feed tap fixing type SVR. It is possible to prevent the system voltage from becoming abnormal when a power flow occurs. However, when a reverse power flow occurs in the SVR due to the fact that the distributed power sources are linked to the system, it may not be possible to perform proper voltage adjustment using the reverse feed tap fixed SVR. is there. In order to show this, the operation of the general type SVR and the reverse tap fixed type SVR in various power flow states will be described with reference to FIGS.

  FIGS. 10A to 10C each show a power distribution substation connected to the primary side of the SVR in the distribution system where the general type SVR is installed, and the power flow in the SVR is in the forward flow state. When the system is switched, the power substation of another system is connected to the secondary side of the SVR, and a reverse power flow occurs in the SVR, and the power substation is connected to the primary side of the SVR. When the SVR performs the adjustment operation, a single line connection diagram showing the state of the system when the reverse flow of power is generated in the SVR due to the connection of the distributed power supply on the secondary side of the SVR is connected It is explanatory drawing shown with the graph which shows the change of the voltage distribution of the system | strain which arises.

  11 (A) to 11 (C), respectively, in the distribution system in which the reverse feed tap fixing type SVR is installed, a power substation is connected to the primary side of the SVR, and the power flow in the SVR is normal. When the power flow is in a directional state, the power supply substation of another system is connected to the secondary side of the SVR by switching the system, and a reverse power flow occurs in the SVR, and the primary side of the SVR Is connected to the power supply substation, but a single-line diagram showing the state of the system when a reverse power flow occurs in the SVR due to the connection of the distributed power supply on the secondary side of the SVR It is explanatory drawing shown with the graph which shows the change of distribution.

  In the single-line connection diagrams shown in FIGS. 10A to 10C and FIGS. 11A to 11C, 1 indicates a substation (power supply substation) which is a power source of the system, and 2 indicates a substation 1 The SVR connected through the switch 3 and the distribution line 4 is shown. Reference numeral 5 denotes a distribution line having one end connected to the secondary side of the SVR, and reference numeral 6 denotes a distribution line of another system connected to the other end of the distribution line 5 via a switch 7. 10 (C) and 11 (C), 8 indicates a distributed power source connected to the distribution line 5 on the secondary side of the SVR. In the graphs shown in FIGS. 10 and 11, max and min indicate the upper limit value and the lower limit value of the system voltage setting range, respectively.

  As shown in FIG. 10 (A), in the distribution system in which the general type SVR is installed, the system is not switched, and the distribution line on the primary side of the SVR is connected to the power substation, When the power flow in the SVR is a forward power flow state, as shown by the broken line in the figure, when the system voltage is about to fall below the lower limit value of the setting range, the system voltage is increased by causing the SVR to tap up. Can be kept within the set range, and when the system voltage rises and exceeds the upper limit value of the set range, the system voltage can be kept within the set range by causing the SVR to tap down. When the primary distribution line of the SVR is connected to the power substation and the power flow in the SVR is in the forward power flow state, as shown in FIG. The same operation as that of the type SVR is performed.

  Further, in the distribution system in which the general type SVR is installed, as shown in FIG. 10B, the distribution line on the secondary side of the SVR is connected to the power substation of another system by switching the system. When the power flow in the SVR becomes a reverse power flow state, the SVR increases the secondary side voltage when the secondary system voltage is about to fall as shown by the broken line in the figure. If the tap is raised as much as possible, the primary side voltage will be pushed down as a result, and an abnormal state may occur in which the system voltage on the primary side of the SVR falls below the lower limit value of the setting range. Also, when the system voltage is going to rise beyond the upper limit of the set range, if the SVR taps down to lower the secondary side voltage, the primary side voltage will be boosted, resulting in the primary of the SVR. An abnormal state may occur in which the system voltage on the side exceeds the upper limit value of the setting range.

  On the other hand, in the distribution system in which the reverse feed tap fixed type SVR is installed, when the power flow in the SVR becomes a reverse power flow state due to the system switching, the power flow judgment function of the SVR has the primary side As shown in FIG. 11 (B), the secondary voltage of the SVR is going to be lowered to perform the operation of fixing the tap of the adjustment transformer to the tap specified in advance so as to increase the system voltage of Sometimes the primary side voltage is raised, and when the secondary side voltage is going to rise, the primary side voltage is lowered to keep the system voltage in the set range.

  As described above, in order to prevent the system voltage from being abnormally lowered or raised when a reverse power flow occurs in the SVR due to the system switching, as a SVR, the tap fixing type SVR for reverse feed is used. However, if a power supply substation is connected to the primary side of the SVR and a distributed power supply is linked to the grid on the secondary side of the SVR, a reverse power flow occurs in the SVR. As shown in FIG. 4, when the reverse feed tap fixed type SVR is used, a phenomenon may occur in which the system voltage on the secondary side of the SVR is abnormally lowered.

  In the distribution system where the general type SVR is installed, as shown in FIG. 10 (C), the distribution line on the primary side of the SVR is connected to the power substation and distributed to the system on the secondary side. When a reverse power flow state occurs in the SVR due to the power supply being connected, the secondary system voltage is within the set range as shown by the broken line in FIG. When an attempt is made to increase beyond the upper limit, the SVR taps down and performs an adjustment operation to keep the system voltage in the set range. When the secondary system voltage is going to fall below the lower limit value of the setting range, the SVR performs tap adjustment to perform an adjustment operation to keep the primary system voltage within the setting range. Therefore, in the distribution system in which the general type SVR is installed, the distribution line on the primary side of the SVR is connected to the power substation, and the distributed power supply is connected on the secondary side, so that the power of the SVR is Even in a state where reverse power flow occurs, the system voltage can be kept within the set range.

  On the other hand, in the distribution system in which the reverse feed tap fixing type SVR is installed, as shown in FIG. 11C, the switch 3 of the substation 1 is closed and the primary distribution line of the SVR is connected to the power substation. 1, when a reverse power flow occurs in the SVR due to the connection of the distributed power supply 8 to the system on the secondary side of the SVR, the primary voltage is increased during the reverse flow. As shown in FIG. 11, the adjustment transformer tap is fixed to the tap specified in advance, but the primary voltage of the SVR connected to the power substation is fixed by the large-capacity system voltage. As shown in (C), the secondary side voltage may be pushed down and an abnormal state may occur in which the secondary system voltage falls below the lower limit value min of the setting range.

  From the above, when a reverse power flow occurs in the SVR due to system switching, and because the distributed power supply is linked to the secondary system while the primary distribution line is connected to the power substation, the SVR In order to maintain the system voltage in an appropriate range in any case where a reverse power flow occurs, when the reverse power flow occurs in the SVR due to the system switching, the SVR is a tap-fixed SVR for reverse feed. When a reverse power flow occurs in the SVR because the distributed power supply is linked to the system, it is understood that it is necessary to operate the SVR in the operation mode of the general type SVR.

  In order to switch the operation mode of the SVR as described above, when a reverse power flow occurs in the SVR, the cause of the reverse power flow is caused by system switching, or the secondary side of the SVR having a power source on the primary side. Therefore, it is necessary to determine whether it is caused by the fact that the distributed power supply is linked to the system.

  When the reverse feed tap fixed type SVR is used, the tap of the adjustment transformer of the SVR is once passed through the passing control command given from the command station provided in the substation when the system is switched. The through control to switch to is performed. Therefore, when a through control command is given when a reverse power flow is detected in the SVR, the cause of the reverse power flow is that the system has been switched, and the power change in the SVR If the through control command is not given when the reverse power flow is detected, it can be temporarily determined that the cause of the reverse power flow is that the distributed power supply is linked to the system. However, in order to switch the operation mode of the SVR without error, it is preferable that the cause of the reverse power flow is also performed by another method so that the cause is accurately identified. Also, in a system that does not perform through control, in order to switch the operation mode at the time of reverse power flow of the SVR appropriately, a method for determining the cause of reverse power flow without using the through control command is established. It is essential.

  Therefore, as described in Patent Document 1, the present applicants and others previously described the amount of change in the primary voltage of the SVR generated when tap switching is performed in a state where a reverse power flow is detected and A method to identify the cause of reverse power flow from the amount of change in secondary voltage was proposed. In this method, when the distribution line on the primary side of the SVR is connected to the power supply substation, the amount of change in the voltage generated on the primary side (substation side) of the SVR having a large system capacity at the time of tap switching is SVR. Focusing on the fact that it becomes smaller than the amount of change in voltage generated on the secondary side (load side), the cause of the reverse power flow is determined.

The relationship between the state of the system and the change amount of the primary side voltage and the change amount of the secondary side voltage at the time of tap switching is shown in FIG. The relationship shown in FIG. 12 is as follows (a) to (c).
(I) When the distribution line on the primary side of the SVR is connected to the power substation and power is flowing in the forward direction through the SVR:
When tapping is performed with the SVR, the secondary voltage of the SVR rises almost stepwise, but the primary voltage hardly changes.
Further, when the tap is lowered by SVR, the secondary voltage of SVR drops almost stepwise, but the primary voltage hardly changes.
(Ii) Since the SVR primary distribution line was disconnected from the power substation and the secondary distribution line was connected to the substation of another system (system switching was performed) When:
When tapping is performed with the SVR, the primary voltage of the SVR drops almost stepwise (changes to the negative side). At this time, the secondary voltage of the SVR rises stepwise, but the amount of change is slight.
In addition, when the tap is lowered by SVR, the primary side voltage increases almost stepwise (changes to the positive side). At this time, the secondary voltage of the SVR slightly decreases, but the amount of change is small.
(Iii) When SVR primary side distribution lines are connected to the substation and the distributed power supply is linked to the secondary side and power is flowing backward through the SVR:
When tapping is performed with the SVR, the secondary voltage of the SVR rises stepwise. The primary voltage of the SVR decreases slightly, but the amount of change is small.
Further, when the tap is lowered by SVR, the secondary side voltage drops stepwise. At this time, the primary voltage of the SVR slightly increases, but the amount of change is small.

  Since there is a relationship as described above between the system state and changes in the primary side voltage and the secondary side voltage at the time of SVR tap switching, tap switching is performed in a state where a reverse power flow is detected by SVR. By determining the relationship between the amount of change in the primary side voltage and the amount of change in the secondary side voltage that occurs when the operation is performed, it is possible to determine the cause of the reverse power flow.

  In the method disclosed in Patent Document 1, a change in voltage generated on the primary side and the secondary side of the SVR is measured, and it is measured that a reverse power flow occurs in the SVR, and the tap is switched. When it is measured that the amount of change in the primary voltage of the SVR that is larger than the amount of change in the secondary voltage is measured, the distribution line on the primary side of the SVR is disconnected from the power substation and the distribution line on the secondary side Determines that a reverse power flow has occurred due to the system switching connected to the power substation of another system. Also, when it is measured that a reverse power flow has occurred in the SVR, and it is measured that the amount of change in the secondary voltage of the SVR that occurs when the tap is switched is greater than the amount of change in the primary voltage In addition, when the SVR primary side distribution line is connected to the power substation, a reverse power flow occurs due to the distributed power supply connected to the secondary side system of the SVR. judge.

  In other words, in the method disclosed in Patent Document 1, in a state where a reverse power flow occurs in the SVR, the change between the change amount of the primary side voltage and the change amount of the secondary side voltage measured at the time of tap switching is “ When there is a relationship of primary voltage change <secondary voltage change, it is determined that the power source is on the primary side of the SVR, and the cause of the reverse power flow in the SVR is the secondary side of the SVR. In this case, it is determined that the distributed power supply is linked to the system, and the power supply is on the secondary side of the SVR when there is a relationship of “amount of change in the primary side voltage> amount of change in the secondary side voltage”. It is determined that the cause of the reverse power flow is that the system has been switched.

  In the description below, the SVR primary distribution line is disconnected from the power substation and the secondary side distribution line is connected to another power supply substation. The reverse power flow that occurs is called “reverse power flow caused by system switching”. When the primary distribution line of the SVR is connected to the power substation, a distributed power source is connected to the secondary system of the SVR. The reverse power flow that occurs in the SVR due to the interconnection is referred to as “the reverse power flow caused by the connection of the distributed power sources”.

JP 2000-295774 A

  In order to accurately identify the cause of the reverse power flow by the method disclosed in Patent Document 1, the amount of change in the primary side voltage and the amount of change in the secondary side voltage that occur when the tap is switched are accurately determined. Need to be measured. In the conventional method, the period from when the SVR starts the tap switching operation to the end of the switching operation is taken as a measurement period, and the SVR primary voltage and secondary voltage are generated at a certain time interval. Measured, the absolute value of the difference between the measured value of the primary side voltage measured at each measurement timing and the measured value of the primary side voltage measured at the previous measurement timing was sequentially obtained as the amount of change in the primary side voltage . Similarly, the absolute value of the difference between the measured value of the secondary side voltage measured at each measurement timing and the measured value of the secondary side voltage measured at the previous measurement timing is sequentially used as the amount of change in the secondary side voltage. Every time the amount of change in the primary voltage and the amount of change in the secondary voltage at the time of tap switching is found, the difference between the two is calculated as the voltage change amount difference, and from the magnitude relationship of this voltage change amount difference , Was determining the state of the system. However, in such a determination method, immediately after the SVR performs the voltage adjustment operation (tap switching), the determination may be erroneous if the primary side voltage and the secondary side voltage of the SVR fluctuate due to system load fluctuations. there were.

  As an example, in a state where a reverse power flow is generated due to the fact that the distributed power supply is linked to the system on the secondary side of the SVR while the distribution line on the primary side of the SVR is connected to the power substation, The reason why the erroneous determination occurs will be described by taking as an example a case where the tap is switched in the direction in which the secondary voltage of the SVR is lowered.

  FIG. 9A shows a measurement command signal for determining a period during which the primary voltage and the secondary voltage of the SVR are measured. This signal is a rectangular wave signal indicating different levels in the measurement period Ta and other periods. is there. The measurement period Ta is set so as to include a period during which the SVR performs a tap switching operation. Normally, the tap switching device of the SVR rotates a drive shaft by a motor when a tap switch command is given, and a series of steps necessary to switch the tap of the adjustment transformer while the drive shaft rotates by a predetermined angle. Let's do the operation. The measurement period starts, for example, at a timing when a tap switching command is given, and is set to end at a timing when a certain time has passed after the tap of the adjustment transformer is switched to a new tap.

  FIGS. 9B and 9C show the state of the primary voltage of the SVR generated when the tap is lowered in the SVR in the state where the reverse flow of the electric power occurs in the SVR due to the cooperation of the distributed power sources. The change and the change of a secondary side voltage are shown. When the SVR's primary distribution line is connected to the substation and the distributed power supply is linked on the secondary side, power is flowing in the reverse direction through the SVR, and when tapping down with the SVR, As shown by the solid line in FIG. 9 (B), the primary side voltage hardly changes, but the secondary side voltage drops almost stepwise at the time of tap switching as shown by the solid line in FIG. 9 (C). To do. The voltage change indicated by symbol a in FIG. 9C is a change that occurs in the secondary side voltage when the tap is switched. When a reverse flow of power is detected in the SVR, when it is measured that the change amount of the secondary side voltage at the time of the tap switching is larger than the change amount of the primary side voltage, the reverse flow of the power It can be determined that the cause of this is that the distributed power supply is linked to the system on the secondary side of the SVR.

  In the conventional method, with the timing t1 when the measurement command signal is generated as the first measurement timing, the primary voltages V11, V12,..., SVR at the measurement timings t1, t2, t3,. V1n and secondary side voltages V21, V22,..., V2n are measured, and the measured value of the primary side voltage measured at each measurement timing tk (k = 3, 4,..., N) and the measurement timing tk two times before. The absolute value of the difference from the measured value of the primary side voltage measured in -2 is sequentially obtained as a change amount ΔV1k = | V1k−2−V1k | of the primary side voltage. Similarly, the absolute value of the difference between the measured value of the secondary side voltage measured at each measurement timing and the measured value of the secondary side voltage measured at the previous measurement timing is calculated as the change amount ΔV2k of the secondary side voltage = | V2k-2−V2k | is calculated sequentially, and the primary voltage change amount and the secondary voltage change amount are calculated each time the primary side voltage change amount ΔV1k and the secondary side voltage change amount ΔV2k are calculated. The difference ΔVk = ΔV1k−ΔV2k is obtained as a voltage change amount difference, and it is determined whether the sign of the voltage change amount ΔVk is positive or negative. As a result, when it is measured that the voltage change amount difference ΔVk is positive and the absolute value is greater than or equal to the threshold value, it is determined that a reverse power flow has occurred in the SVR due to system switching. Further, when it is measured that the voltage change difference ΔVk is negative and the absolute value thereof is equal to or greater than the threshold value, it is determined that a reverse power flow is generated in the SVR due to the interconnection of the distributed power sources. To do.

  In the example shown in FIG. 9, when the primary side voltage and the secondary side voltage change as indicated by solid lines in the figure, at the measurement timing tn-1, ΔV1n-1 = | V1n-3−V1n− 1 |, ΔV2n−1 = | V2n−3−V2n−1 | are calculated and it is determined that ΔVn−1 = ΔV1n−1−ΔV2n−1 <0. It can be determined that a reverse power flow has occurred due to the linkage.

  However, if the primary voltage and the secondary voltage of the SVR fluctuate as shown by the broken line in FIG. 9 due to the load fluctuation of the system immediately after the tap switching is performed by the adjusting transformer of the SVR, ΔVn Since −1 = ΔV1n−1−ΔV2n−1> 0, it is erroneously determined that a reverse power flow has occurred due to system switching. Further, the proposed method has a problem that it takes time to determine the cause of the reverse power flow because it needs to deal with a lot of sampling data and needs to perform arithmetic processing many times.

  An object of the present invention is to provide an automatic distribution power supply capable of accurately and easily determining the cause when a reverse power flow is measured by an automatic voltage regulator installed in a distribution system. An object of the present invention is to provide a reverse power flow cause determination method for a voltage regulator and a reverse power flow cause determination device used to implement this method.

  The present invention is an automatic voltage regulator for distribution that determines the cause when a reverse power flow occurs from the secondary side to the primary side in the automatic voltage regulator of the tap switching type on load installed in the distribution system. The method for determining the cause of reverse power flow is targeted.

In the determination method according to the present invention, when the automatic voltage regulator performs voltage adjustment in a state where the reverse power flow is detected by the automatic voltage regulator, the timing before the timing at which the tap of the automatic voltage regulator is switched. The first measurement timing set to the timing, the second measurement timing set to the timing immediately after the tap is switched, and the third measurement timing set to a timing slightly delayed from the second measurement timing At the measurement timing, the primary voltage of the automatic voltage regulator is measured as the first primary voltage, the second primary voltage, and the third primary voltage, respectively, and the secondary voltage of the automatic voltage regulator is measured as the first secondary voltage. The following steps (1) to (4) are performed by measuring the voltage, the second secondary voltage, and the third secondary voltage.
(1) A comparison between the second primary voltage and the third primary voltage and / or a comparison between the second secondary voltage and the third secondary voltage, and from the result of the comparison, an automatic voltage regulator The load state of the system immediately after the voltage adjustment operation is performed is a state where there is no load variation, a light load variation where the load on the system is light, and a heavy load variation where the load on the system is heavy A load state determination process for determining which of the states.
(2) When the voltage adjustment operation performed by the automatic voltage regulator assumes that a power substation is connected to the distribution line on the primary side of the automatic voltage regulator and power is flowing in the forward direction through the automatic voltage regulator Voltage adjustment operation for determining whether the tap is to be switched in the direction in which the secondary side voltage of the automatic voltage regulator is boosted or whether the tap is to be switched in the opposite direction to that when the tap is raised Judgment process.
(3) A comparison between the first primary voltage and the third primary voltage and / or a comparison between the first secondary voltage and the third secondary voltage is performed to determine the relationship between the compared voltages. Voltage change judgment process at tap switching.
(4) The determination result in the load state determination process, the determination result in the voltage adjustment operation determination process, and the determination result in the voltage change determination process at tap switching are collated with the determination requirements prepared in advance for these determination results. The cause of the reverse power flow is that the distributed power supply is linked to the distribution line on the secondary side of the automatic voltage regulator while the distribution line on the primary side of the automatic voltage regulator is connected to the power substation. This is because the distribution line on the primary side of the automatic voltage regulator was disconnected from the power substation by switching the system, and the distribution line on the secondary side was connected to the power substation of another system. Reverse power flow cause determination process to determine whether or not.

  As described above, when the automatic voltage regulator performs voltage adjustment in a state where the reverse power flow is detected in the SVR, the first time set before the timing at which the tap is switched is set. The automatic voltage regulator at the measurement timing, the second measurement timing set immediately after the tap is switched, and the third measurement timing set slightly later than the second measurement timing When the primary side voltage is measured as the first to third primary voltages and the secondary side voltage is measured as the first to third secondary voltages, the second primary voltage and the third primary voltage are measured. From the high / low relationship and / or the high / low relationship between the second secondary voltage and the third secondary voltage, the load state of the system immediately after the automatic voltage regulator performs the voltage adjustment operation is ) No change in system load, Whether the system is in a state where a light load fluctuation, which is a fluctuation in the direction of lightening the system load, or (c) a state of heavy load fluctuation, which is a fluctuation in the direction of increasing the system load, is present I found out that it can be distinguished.

  Further, the determined load state of the system, the determination result of whether the voltage adjustment operation executed by the automatic voltage regulator is tap-up or tap-down, and the first measurement timing and the third measurement timing, respectively. Comparison determination result between primary voltages measured (change in primary voltage immediately after tap switching) and / or comparison determination result between secondary voltages (change in secondary voltage immediately after tap switching) and automatic voltage adjustment Therefore, there is a certain relationship between the cause of the reverse power flow generated in the transformer, and therefore, the judgment result in the load state judgment process, the judgment result in the voltage adjustment operation judgment process, and the voltage change judgment process at tap switching By comparing the judgment results obtained in step 1 with the judgment requirements prepared in advance for these judgment results, the cause of the reverse power flow in the automatic voltage regulator is the distribution of the primary side of the automatic voltage regulator. Electrical wire Whether the distributed power supply is linked to the distribution line on the secondary side of the automatic voltage regulator while connected to the power supply substation, or the primary distribution line on the automatic voltage regulator is connected to the power supply substation by switching the system It was found that it is possible to determine whether the secondary distribution line is connected to a power substation of another system.

  The power reverse flow cause determination device of the automatic voltage regulator for distribution that implements the above judgment method is automatic when the automatic voltage regulator performs voltage adjustment in the state where the reverse flow of power is detected by the automatic voltage regulator. From the first measurement timing set at the timing before the timing when the tap of the voltage regulator is switched, the second measurement timing set at the timing immediately after the tap is switched, and the second measurement timing The primary voltage of the automatic voltage regulator is measured as the first primary voltage, the second primary voltage, and the third primary voltage, respectively, at the third measurement timing set at a slightly delayed timing, and the automatic voltage Comparison of voltage measuring means for measuring the secondary side voltage of the regulator as the first secondary voltage, the second secondary voltage, and the third secondary voltage, and the second primary voltage and the third primary voltage And (also ) Comparison between the second secondary voltage and the third secondary voltage, and from the comparison result, the load state of the system immediately after the automatic voltage regulator performs the voltage adjustment operation is a state in which there is no load fluctuation. In any state of a state where a light load variation, which is a variation in a direction in which the load on the system is lightened, and a state in which a heavy load variation, which is a variation in a direction in which the load on the system is heavy, are occurring The load condition determination means for determining whether or not there is a voltage adjustment operation performed by the automatic voltage regulator, the secondary voltage of the automatic voltage regulator is set with the power supply substation connected to the primary side of the automatic voltage regulator. Voltage adjustment operation determination means for determining whether the tap is to be switched in the direction of boosting, or to be a tap lowering to switch the tap in the direction opposite to that when the tap is lifted; and the first primary voltage and the third primary voltage And / or second The comparison between the secondary voltage and the third secondary voltage is performed, and the voltage change determination means at the time of tap switching for determining the relationship between the levels of the compared voltages, the determination result by the load state determination means, and the voltage adjustment operation determination By comparing the determination result by the means and the determination result by the voltage change determination means at the time of tap switching with the determination requirements prepared in advance for these determination results, the cause of the reverse power flow is the automatic voltage Whether the distributed power supply is linked to the secondary distribution line of the automatic voltage regulator while the primary distribution line of the regulator is connected to the power substation, or the automatic voltage regulator Constructed by including reverse power flow cause determination means for determining whether the primary distribution line is disconnected from the power supply substation and the secondary distribution line is connected to the power supply substation of another system Is done.

  According to the present invention, the first measurement timing set at a timing before the timing at which the tap of the automatic voltage regulator is switched, the second measurement timing set at the timing immediately after the tap is switched, and The primary voltage of the automatic voltage regulator is changed to the first primary voltage, the second primary voltage, and the third primary voltage at the third measurement timing set at a timing slightly delayed from the second measurement timing, respectively. And measuring the secondary side voltage as the first secondary voltage, the second secondary voltage, and the third secondary voltage, and measuring the second primary voltage immediately after the tap switching is performed. The automatic voltage regulator performs a voltage adjustment operation based on the high-low relationship between the voltage and the third primary voltage and / or the high-low relationship between the second secondary voltage and the third secondary voltage. The load status of the system immediately after The determination result of whether the voltage adjustment operation is a tap-up or tap-down, the first primary voltage and the third primary voltage measured before and after the voltage adjustment operation, while considering the determination result of the load state Since the cause of the reverse power flow is determined based on the high / low relationship between the voltage and / or the high / low relationship between the first secondary voltage and the third secondary voltage, automatic Even when a load fluctuation occurs in the system immediately after the voltage adjustment operation is performed in a state where the reverse flow of power is generated in the voltage regulator, the cause of the reverse flow can be accurately identified. According to the present invention, the determination of the load state immediately after the voltage adjustment operation is performed from the comparison determination result between the primary voltages and the secondary voltages respectively measured at the first measurement timing to the third measurement timing; Since the cause of the reverse power flow is identified, the reverse power flow can be generated simply by comparing the voltages without handling a lot of sampling data or repeating the operation many times. Cause can be identified.

It is the block diagram which showed schematically the structure of the hardware of one Embodiment of this invention. It is the block diagram which showed the structure of one Embodiment of this invention containing each means comprised by a microprocessor. It is the connection diagram which showed an example of the structure of the automatic voltage regulator. (A) to (C) show the reverse power flow in the distribution system where the SVR is installed, because the distribution line on the primary side of the SVR is connected to the power substation and the distributed power supply is linked to the secondary side. It is the graph which showed the voltage change when tapping is performed in the state where the occurrence has occurred with respect to various load states of the system. (A) to (C) show the reverse power flow in the distribution system where the SVR is installed, because the distribution line on the primary side of the SVR is connected to the power substation and the distributed power supply is linked to the secondary side. It is the graph which showed the voltage change when tap lowering was performed in the state which has occurred with respect to various load conditions of a system. In (A) to (C), in the distribution system where the SVR is installed, the primary distribution line of the SVR is disconnected from the power supply substation, and the secondary distribution line is connected to the power supply substation of another system. It is the graph which showed the voltage change when tapping was performed in the state where the reverse power flow has arisen by this with respect to the various load conditions of a system | strain. In (A) to (C), in the distribution system where the SVR is installed, the primary distribution line of the SVR is disconnected from the power supply substation, and the secondary distribution line is connected to the power supply substation of another system. It is the graph which showed the voltage change when the tap lowering was performed in the state in which the reverse power flow has arisen by this with respect to the various load conditions of a system | strain. (A) to (C) respectively show the relationship between the voltage regulation operation of the automatic voltage regulator and the change of the primary voltage and the secondary voltage and the cause of the reverse power flow, when there is no load fluctuation in the system during the reverse power flow. A chart showing when a light load fluctuation, which is a fluctuation in the direction of lightening the load in the system during reverse power flow, and a heavy load fluctuation, a fluctuation in the direction of increasing the load in the system, during reverse power flow It is. It is a signal waveform diagram of each part used in order to explain the conventional judgment method. (A) to (C), respectively, in a distribution system in which a general automatic voltage regulator is installed, when the power flow in the automatic voltage regulator is in a forward flow state, the automatic voltage regulator is switched by switching the system. A single-line diagram showing the state of the system when the reverse power flow occurs and when the automatic voltage regulator causes a reverse power flow due to the interconnection of distributed power sources, the change in the voltage distribution of the system It is explanatory drawing shown with the graph to show. (A) to (C), respectively, in the distribution system in which the reverse feed tap fixed automatic voltage regulator is installed, when the power flow in the automatic voltage regulator is in the forward flow state, A single-line diagram showing the state of the system when reverse power flow occurs in the automatic voltage regulator and when reverse power flow occurs in the automatic voltage regulator due to the interconnection of distributed power sources. It is explanatory drawing shown with the graph which shows the change of distribution. It is the graph which showed collectively the relationship between the state of a system | strain, the change of the primary side voltage at the time of tap switching, and the change of a secondary side voltage.

  FIG. 1 schematically shows an example of the hardware configuration of an apparatus that implements the reverse power flow cause determination method according to the present invention. In the figure, 2 is an automatic voltage regulator, 4 is a U, V, W three-phase one end connected to a transformer in a substation (not shown) via a switch and the other end connected to the primary side of the automatic voltage regulator. Primary side distribution line. 5 is a U, V, W three-phase secondary distribution line with one end connected to the secondary side of the automatic voltage regulator 2 and the other end connected to a distribution line of another system via a switch. is there.

  The automatic voltage regulator 2 is configured as shown in FIG. 3, for example. In FIG. 3, reference numeral 2A denotes a regulating transformer composed of a single-winding transformer having taps a1 to a9, and 2B denotes a load-time tap switching device for switching taps of the regulating transformer. The voltage of the distribution line 4 is input to the primary side of the adjustment transformer 2A through the on-load tap switching device 2B. The secondary side of the adjustment transformer 2 </ b> A is connected to the distribution line 5. 2C is a voltage transformer (PT) for measuring the secondary side voltage V1 of the automatic voltage regulator, and 2D is a voltage regulating relay for giving a tap switching command to the tap switching device 2B so as to keep the secondary side voltage at the target voltage. (90 relay) 2E is a line voltage drop compensator (LDC) connected in series with the voltage adjustment relay 2D. The series circuit of the voltage adjustment relay 2D and the line voltage drop compensator 2E is an instrument transformer 2C. Is connected between the output terminals of The output of the current transformer (CT) 2F that measures the load current IL flowing through the secondary distribution line 5 is input to the LDC 2E. V1 and V2 are the primary side voltage and the secondary side voltage of the automatic voltage regulator, respectively.

  In the automatic voltage regulator shown in FIG. 3, the voltage regulating relay 2D measures the secondary side voltage V2 from the output voltage VL 'of the instrument transformer 2C, and the secondary side distribution line from the primary side distribution line 4 side. When power is being sent to the side 5 (during progressive power feeding), a tap switching command is given to the tap switching device 2B so as to keep the secondary side voltage V2 at the target voltage. The tap switching device 2B switches the tap of the adjusting transformer 2A according to the tap switching command given from the voltage adjusting relay 2D so as to keep the secondary voltage V2 of the automatic voltage regulator at the target voltage (secondary side). Adjust so that the difference between the voltage V2 and the target voltage is within the allowable range.

  That is, when the secondary side voltage V2 becomes lower than the target voltage during the forward power transmission, the voltage adjustment relay 2D generates a step-up command, thereby performing a tap up to switch the tap of the adjustment transformer 2A to the step-up side. The voltage is adjusted so that the difference between the secondary side voltage V2 and the target voltage is within an allowable range. Further, when the secondary side voltage V2 exceeds the target voltage, the voltage adjusting relay 2D generates a step-down command, thereby performing a tap lowering to switch the tap of the adjusting transformer 2A to the step-down side, and the secondary side voltage and the target voltage. Adjust the voltage so that the difference between the two is less than the allowable range.

  The line voltage drop compensator 2E is composed of a resistance and a reactance simulating the line impedance of the distribution line 5, and is provided so that an output current ILDC of CT2F flows through the resistance and the reactance. At both ends of the line voltage drop compensator 2E, a voltage drop VLDC proportional to the voltage drop due to the line impedance occurs. At this time, the voltage V90 applied to the voltage adjusting relay 2D is V2-VLDC, which is lower by VLDC than when the line voltage drop compensator 2E is not inserted. Therefore, the voltage regulation relay 2D gives a tap switching command to the on-load tap switching device 2B so as to switch the tap of the regulation transformer 2A to the boost side by the line voltage drop VLDC to compensate for the voltage drop due to the line impedance.

  In FIG. 1, reference numeral 10 denotes a current transformer provided on the secondary side of the automatic voltage regulator, to which a W-phase current and a U-phase current whose phase is inverted are input, and 11 is an output of the current transformer 10. In the reverse power relay, the current transformer 10 and the reverse power relay 11 constitute a power reverse flow detector 12. Reference numerals 13 and 14 are transformers (PT) for measuring the primary side voltage V1 and the secondary side voltage V2 from the U and W phases of the automatic voltage regulator, respectively. The measurement signals of the primary side voltage and the secondary side voltage obtained from the instrument transformers 13 and 14 are first and second through the primary side voltage detection circuit 15 and the secondary side voltage detection circuit 16 each having a load resistance. The signals are input to A / D converters 17 and 18 and converted into digital signals. Reference numeral 19 denotes a measurement command signal generating means for generating a measurement command signal when the tap switching device of the automatic voltage regulator performs tap switching in a state where the power reverse flow detection device 12 detects the reverse power flow.

  When the automatic voltage regulator 2 performs voltage adjustment in a state where the power reverse flow detection device 12 detects that the reverse flow of power has occurred in the automatic voltage regulator 2, the measurement command signal generation means 19 As shown in FIGS. 4 to 7, the first measurement timing ta set at a timing before the timing t1 at which the tap of the automatic voltage regulator 2 is switched, the timing immediately after the tap is switched. The first measurement command signal, the second measurement command signal, and the second measurement timing tb set at a timing slightly behind the second measurement timing tb and the third measurement timing tc set slightly later than the second measurement timing tb, respectively. A third measurement command signal is generated.

  Digital signals obtained from the first and second A / D converters 17 and 18 are input to the microprocessor 20 together with the output of the power reverse flow detector 12 and the output of the measurement command signal generator 19. The microprocessor 20 constitutes means for performing various functions by executing a predetermined program.

  FIG. 2 shows the configuration of the determination apparatus according to the present embodiment including function realizing means constituted by the microprocessor 20. In the present embodiment, the microprocessor 20 includes a voltage measuring unit 22, a load state determining unit 23, a voltage adjustment operation determining unit 24, a tap switching voltage change determining unit 26, and a reverse power flow cause determining unit 27. To do.

  When the automatic voltage regulator 2 performs voltage adjustment in a state in which the power reverse flow detection device 12 detects that the reverse flow of power has occurred in the automatic voltage regulator 2, the voltage measuring means 22 When the signal generating means 19 generates the first to third measurement command signals at the first measurement timing ta, the second measurement timing tb, and the third measurement timing tc, respectively, the primary side voltage of the SVR 2 is changed to the first voltage. The first primary voltage V1a, the second primary voltage V1b, and the third primary voltage V1c are measured. The voltage measuring means 22 also generates the first to third measurement command signals at the first measurement timing ta, the second measurement timing tb, and the third measurement timing tc, respectively. In addition, the secondary side voltage of SVR2 is measured as a first secondary voltage V2a, a second secondary voltage V2b, and a third secondary voltage V2c.

  The load state determination means 23 is a means for determining the load state of the system immediately after the SVR performs voltage adjustment, and whether or not there is a load change in the system immediately after the SVR performs the voltage adjustment operation (performs tap switching). And means for determining the content of the load fluctuation. The load state determination means 23 compares the second primary voltage V1b and the third primary voltage V1c and / or compares the second secondary voltage V2b and the third secondary voltage V2c, and compares them. From the results, the load state of the system immediately after voltage adjustment is in a state where there is no load change, a light load change that is a change in the direction of lightening the system load, and a direction in which the load of the system becomes heavy It is determined which state is in the state where the heavy load fluctuation, which is the fluctuation of, is occurring.

  Note that “the state where there is no load fluctuation” does not mean only when the fluctuation of the load is zero, but is a parameter (first to third primary voltages and first and third parameters) used for determining the cause of the reverse power flow. Or a third secondary voltage) (a period between the first measurement timing and the third measurement timing), and a voltage that is negligible compared to the voltage fluctuation when the tap is switched. It also includes the state where fluctuation occurs.

  The voltage adjustment operation determination means 24 automatically performs the voltage adjustment operation performed by the automatic voltage regulator from the tap switching command generated by the voltage adjustment relay 2D in a state where the power substation is connected to the primary side of the automatic voltage regulator. It is a means for determining whether the tap-up is to switch the tap in the direction of increasing the secondary side voltage of the voltage regulator or the tap-down is to switch the tap in the opposite direction to the tap-up. Whether the voltage adjustment operation performed by the SVR 2 is tap-up or tap-down can be determined from a tap switching command generated by the voltage adjustment relay 2D.

  The tap change voltage change judging means 26 compares the first primary voltage V1a with the third primary voltage V1c and / or compares the first secondary voltage V2a with the third secondary voltage V2c. Thus, it is a means for determining the relationship between the levels of the compared voltages.

  The reverse power flow cause determination means 27 prepares in advance a determination result in the load state determination process, a determination result in the voltage adjustment operation determination process, and a determination result in the voltage change determination process at tap switching for these determination results. By comparing with the judgment requirements, the cause of reverse power flow is caused by the distribution line on the secondary side of the automatic voltage regulator with the distribution line on the primary side of the automatic voltage regulator connected to the power substation. Whether the distributed power supply is linked or not, the distribution line on the primary side of the automatic voltage regulator is disconnected from the power substation by switching the system, and the distribution line on the secondary side is connected to the power substation of the other system This is a means for determining whether or not there is a problem.

  The present inventor examined in detail the primary side voltage and the secondary side voltage of the SVR observed when the SVR 2 performs the voltage adjustment operation in a state where the reverse power flow is detected in the SVR 2. As a result, when the primary voltage V1 and the secondary voltage V2 of the SVR 2 are measured at the first to third measurement timings ta, tb, and tc set before and after the voltage adjustment operation of the SVR, the SVR performs the measurement. Whether the voltage adjustment operation is tapping or tapping, there is a certain relationship between the measured voltage and the load state of the system, and between the measured voltage and the cause of reverse power flow, From these relationships, it was found that the load state of the system and the cause of reverse power flow can be determined. Hereinafter, the primary side voltage and the secondary side voltage of the SVR observed when the SVR 2 performs the voltage adjustment operation in the state where the reverse power flow is generated in the SVR 2 will be described in detail with reference to FIGS. explain.

  FIG. 4 shows the secondary side of SVR2 in a state where the primary side distribution line of SVR2 is connected to the power supply substation of this system and the secondary side distribution line of SVR2 is disconnected from the power supply substation of the other system. The SVR performs “tap-up” when a reverse power flow occurs in the SVR2 due to the fact that the distributed power supply is linked to (the distributed power supply is connected to the distribution line on the secondary side). The change in primary voltage and secondary voltage of SVR2 when (A) there is no load fluctuation in the system immediately after the tap is raised, (B) light load fluctuation in the system immediately after the tap is raised (Fluctuation in the direction of lightening the system load) and (C) Heavy load fluctuation (fluctuation in the direction of increasing system load) immediately after the tap is raised These three cases are schematically shown.

  When there is no load fluctuation in the system immediately after tapping in the state where the reverse power flow is generated in SVR2, the primary voltage of SVR does not change as shown in FIG. The secondary side voltage increases stepwise at the timing t1 when the tap is switched. In this case, when the second primary voltage V1b measured at the second measurement timing tb is compared with the third primary voltage V1c measured at the third measurement timing tc, V1b = V1c and the second measurement timing is obtained. When the second secondary voltage V2b measured at tb is compared with the third secondary voltage V2c measured at the third measurement timing tc, V2b = V2c. Further, there is a relationship of V1a = V1c between the primary voltage V1a measured at the first measurement timing ta and the primary voltage V1c measured at the third measurement timing tc, and the two measured at the first measurement timing ta. There is a relationship of V2a <V2c between the secondary voltage V2a and the secondary voltage V2c measured at the third measurement timing tc.

  When a light load fluctuation occurs immediately after the tap is raised in the state where the reverse power flow occurs in the SVR2, the primary voltage of the SVR is changed to the tap change as shown in FIG. 4 (B). Immediately after being performed, the voltage increases as the load decreases. The secondary voltage of the SVR increases stepwise at the moment when tap switching is performed, and then increases as the load decreases. In this case, there is a relationship of V1b <V1c between the second primary voltage V1b measured at the second measurement timing tb and the third primary voltage V1c measured at the third measurement timing tc. There is also a relationship of V2b <V2c between the second secondary voltage V2b and the third secondary voltage V2c measured at the measurement timing tb. Further, there is a relationship of V1a <V1c between the primary voltage V1a measured at the first measurement timing ta and the primary voltage V1c measured at the third measurement timing tc, and the two measured at the first measurement timing ta. There is a relationship of V2a <V2c between the secondary voltage V2a and the secondary voltage V2c measured at the third measurement timing tc.

  When a heavy load fluctuation occurs immediately after the tap is raised in the state where the reverse power flow occurs in the SVR2, as shown in FIG. Immediately after being performed, the voltage decreases as the load increases, and the secondary voltage of the SVR increases approximately stepwise at the moment when the tap switching is performed, and then decreases as the load increases. In this case, there is a relationship of V1b> V1c between the second primary voltage V1b measured at the second measurement timing tb and the third primary voltage V1c measured at the third measurement timing tc. There is also a relationship of V2b> V2c between the second secondary voltage V2b and the third secondary voltage V2c measured at the measurement timing tb. Further, there is a relationship of V1a> V1c between the primary voltage V1a measured at the first measurement timing ta and the primary voltage V1c measured at the third measurement timing tc, and the two measured at the first measurement timing ta. There is a relationship of V2a <V2c between the secondary voltage V2a and the secondary voltage V2c measured at the third measurement timing tc.

  FIG. 5 shows the secondary side of SVR2 in a state where the primary side distribution line of SVR2 is connected to the power supply substation of this system and the secondary side distribution line of SVR2 is disconnected from the power supply substation of the other system. When there is a reverse power flow in the SVR2 due to the fact that the distributed power supply is linked to the SVR2, the change in the primary voltage and the secondary voltage of the SVR2 when the SVR "taps down" (A) When there is no load fluctuation in the system immediately after the tap is lowered, (B) When a light load fluctuation (change in the direction in which the load on the system is reduced) occurs immediately after the tap is lowered. And (C) Three cases where heavy load fluctuations (fluctuations in the direction in which the load on the system becomes heavier) occur in the system immediately after the tap is lowered.

  When there is no load fluctuation in the system immediately after the tap is lowered in the state where the reverse power flow occurs in SVR2, the primary side voltage of SVR does not change as shown in FIG. The secondary side voltage drops stepwise at the timing t1 when the tap is switched. In this case, there is a relationship of V1b = V1c between the second primary voltage V1b measured at the second measurement timing tb and the third primary voltage V1c measured at the third measurement timing tc. There is a relationship of V2b = V2c between the second secondary voltage V2b and the third secondary voltage V2c measured at the measurement timing tb. Further, there is a relationship of V1a = V1c between the primary voltage V1a measured at the first measurement timing ta and the primary voltage V1c measured at the third measurement timing tc, and the two measured at the first measurement timing ta. There is a relationship of V2a> V2c between the secondary voltage V2a and the secondary voltage V2c measured at the third measurement timing tc.

  In addition, when a light load fluctuation occurs immediately after the tap is lowered in a state where a reverse power flow occurs in SVR2, the primary voltage of SVR is tapped as shown in FIG. 5B. Immediately after is performed, the voltage increases as the load decreases, and the secondary voltage of the SVR decreases stepwise at the moment when the tap switching is performed, and then increases as the load decreases. In this case, there is a relationship of V1b <V1c between the second primary voltage V1b measured at the second measurement timing tb and the third primary voltage V1c measured at the third measurement timing tc. There is also a relationship of V2b <V2c between the second secondary voltage V2b measured at the measurement timing tb and the third secondary voltage V2c measured at the third measurement timing tc. Further, there is a relationship of V1a <V1c between the primary voltage V1a measured at the first measurement timing ta and the primary voltage V1c measured at the third measurement timing tc, and the two measured at the first measurement timing ta. There is a relationship of V2a> V2c between the secondary voltage V2a and the secondary voltage V2c measured at the third measurement timing tc.

  When a heavy load fluctuation occurs immediately after the tap is lowered in the state where the reverse power flow occurs in SVR2, as shown in FIG. 5C, the primary voltage of the SVR is changed over by tap switching. Immediately after being performed, the voltage decreases as the load increases, and the secondary voltage of the SVR decreases approximately stepwise at the moment when the tap switching is performed, and then decreases as the load increases. In this case, there is a relationship of V1b> V1c between the second primary voltage V1b measured at the second measurement timing tb and the third primary voltage V1c, and the second measured at the second measurement timing tb. There is also a relationship of V2b> V2c between the secondary voltage V2b and the third secondary voltage V2c. Further, there is a relationship of V1a> V1c between the primary voltage V1a measured at the first measurement timing ta and the primary voltage V1c measured at the third measurement timing tc, and the two measured at the first measurement timing ta. There is a relationship of V2a> V2c between the secondary voltage V2a and the secondary voltage V2c measured at the third measurement timing tc.

  FIG. 6 shows that the SVR 2 primary side distribution line is disconnected from the mains power substation and the SVR 2 secondary side distribution line is connected to the other power source substation. Changes in the primary and secondary voltages of the SVR 2 when the SVR performs “tap-up” when a reverse power flow occurs, immediately after (A) voltage adjustment operation (tap switching) When there is no load fluctuation in the system, (B) When a light load fluctuation (change in the direction in which the load on the system becomes lighter) occurs immediately after performing the voltage adjustment operation, and (C) The voltage adjustment operation is performed. This shows three cases where heavy load fluctuations (fluctuations in the direction in which the load on the system becomes heavier) occur in the system immediately after being performed.

  If there is no load fluctuation in the system immediately after tapping in the state where the reverse power flow occurs in SVR2, the secondary side of SVR is connected to a large-capacity power substation. As shown in FIG. 6 (B), the secondary voltage of the SVR does not change, but the primary voltage is pushed down at the timing t1 when the tap is switched and falls stepwise. In this case, there is a relationship of V1b = V1c between the second primary voltage V1b measured at the second measurement timing tb and the third primary voltage V1c measured at the third measurement timing tc. There is also a relationship of V2b = V2c between the second secondary voltage V2b measured at the measurement timing tb and the third secondary voltage V2c measured at the third measurement timing tc. Further, there is a relationship of V1a> V1c between the primary voltage V1a measured at the first measurement timing ta and the primary voltage V1c measured at the third measurement timing tc, and the two measured at the first measurement timing ta. There is a relationship of V2a = V2c between the secondary voltage V2a and the secondary voltage V2c measured at the third measurement timing tc.

  When a light load fluctuation occurs immediately after the tap is raised in the state where the reverse power flow occurs in SVR2, as shown in FIG. 6B, the secondary voltage of SVR is changed over to the tap. Immediately after the operation is performed, the voltage increases as the load decreases. The primary voltage of the SVR decreases stepwise at the moment when the tap switching is performed, and then increases as the load decreases. In this case, there is a relationship of V1b <V1c between the second primary voltage V1b measured at the second measurement timing tb and the third primary voltage V1c measured at the third measurement timing tc. There is also a relationship of V2b <V2c between the second secondary voltage V2b measured at the measurement timing tb and the secondary voltage V2c measured at the third measurement timing tc. Further, there is a relationship of V1a> V1c between the primary voltage V1a measured at the first measurement timing ta and the primary voltage V1c measured at the third measurement timing tc, and the two measured at the first measurement timing ta. There is a relationship of V2a <V2c between the secondary voltage V2a and the secondary voltage V2c measured at the third measurement timing tc.

  When a heavy load fluctuation occurs immediately after the tap is raised in the state where the reverse power flow occurs in the SVR2, as shown in FIG. 6C, the secondary side voltage of the SVR is changed to the tap switching. Immediately after the operation is performed, the voltage decreases as the load increases. The primary voltage of the SVR decreases approximately stepwise at the moment when the tap switching is performed, and then decreases as the load increases. In this case, there is a relationship of V1b> V1c between the second primary voltage V1b measured at the second measurement timing tb and the third primary voltage V1c measured at the third measurement timing tc. There is also a relationship of V2b> V2c between the second secondary voltage V2b and the third secondary voltage V2c measured at the measurement timing tb. Further, there is a relationship of V1a> V1c between the primary voltage V1a measured at the first measurement timing ta and the primary voltage V1c measured at the third measurement timing tc, and the two measured at the first measurement timing ta. There is a relationship of V2a> V2c between the secondary voltage V2a and the secondary voltage V2c measured at the third measurement timing tc.

  FIG. 7 shows that the distribution line on the primary side of SVR2 is disconnected from the power supply substation of this system, and the distribution line on the secondary side of SVR2 is connected to the power supply substation of another system. Changes in the primary and secondary voltages of SVR2 when SVR performs “tap down” when reverse power flow is occurring. (A) Load fluctuations in system immediately after tap increase There are three cases: (B) when a light load fluctuation occurs in the system immediately after tapping, and (C) when a heavy load fluctuation occurs in the system immediately after tapping. It is shown.

  When there is no load fluctuation in the system immediately after tapping in a state where a reverse power flow occurs in SVR2, the secondary voltage of SVR does not change as shown in FIG. 7A. However, the primary voltage rises stepwise at the timing t1 when the tap is switched. In this case, there is a relationship of V1b = V1c between the second primary voltage V1b measured at the second measurement timing tb and the third primary voltage V1c measured at the third measurement timing tc. There is also a relationship of V2b = V2c between the second secondary voltage V2b measured at the measurement timing tb and the third secondary voltage V2c measured at the third measurement timing tc. Further, there is a relationship of V1a <V1c between the primary voltage V1a measured at the first measurement timing ta and the primary voltage V1c measured at the third measurement timing tc, and the two measured at the first measurement timing ta. There is a relationship of V2a = V2c between the secondary voltage V2a and the secondary voltage V2c measured at the third measurement timing tc.

  When a light load fluctuation occurs immediately after the tap is lowered in the state where the reverse power flow occurs in SVR2, as shown in FIG. 7B, the secondary voltage of SVR is tapped. Immediately after the operation is performed, the voltage increases as the load decreases. The primary voltage of the SVR increases stepwise at the moment when the tap is switched, and then increases as the load decreases. In this case, there is a relationship of V1b <V1c between the second primary voltage V1b measured at the second measurement timing tb and the third primary voltage V1c measured at the third measurement timing ta. There is also a relationship of V2b <V2c between the second secondary voltage V2b and the third secondary voltage V2c measured at the measurement timing tb. Further, there is a relationship of V1a <V1c between the primary voltage V1a measured at the first measurement timing ta and the primary voltage V1c measured at the third measurement timing tc, and the two measured at the first measurement timing ta. There is a relationship of V2a <V2c between the secondary voltage V2a and the secondary voltage V2c measured at the third measurement timing tc.

  In addition, when a heavy load fluctuation occurs immediately after the tap is lowered in the state where the reverse power flow occurs in SVR2, the secondary voltage of SVR is changed to the tap as shown in FIG. 7C. Immediately after switching is performed, the voltage decreases as the load increases, and the primary voltage of the SVR increases almost stepwise at the moment when the tap is switched, and then decreases as the load increases. . In this case, there is a relationship of V1b> V1c between the second primary voltage V1b measured at the second measurement timing tb and the third primary voltage V1c measured at the third measurement timing tc. There is also a relationship of V2b> V2c between the second secondary voltage V2b measured at the measurement timing tb and the third secondary voltage V2c measured at the third measurement timing tc. Further, there is a relationship of V1a <V1c between the primary voltage V1a measured at the first measurement timing ta and the primary voltage V1c measured at the third measurement timing tc, and the two measured at the first measurement timing ta. There is a relationship of V2a> V2c between the secondary voltage V2a and the secondary voltage V2c measured at the third measurement timing tc.

From the relationship between the second primary voltage V1b and the third primary voltage V1c and the relationship between the second secondary voltage V2b and the third secondary voltage V2c shown in FIGS. The following can be said.
(A) When there is no load fluctuation immediately after the tap switching, V1b regardless of the cause of the reverse power flow, regardless of whether the voltage adjustment operation is tapping or tapping. = V1c and V2b = V2c.
(B) When a light load change occurs immediately after tap switching, regardless of the cause of the reverse power flow, regardless of whether the voltage adjustment operation is tapping or tapping. , V1b <V1c, and V2b <V2c.
(C) If a heavy load change occurs immediately after tap switching, regardless of the cause of the reverse power flow, and regardless of whether the voltage adjustment operation is tap-up or tap-down V1b> V1c and V2b> V2c.
From the above, the load state determination means 23 shown in FIG. 2 compares the second primary voltage V1b with the third primary voltage V1c and / or the second secondary voltage V2b and the third second voltage V1b. Comparison of the next voltage V2c, and from the comparison result, the load state of the system immediately after the automatic voltage regulator performs the voltage adjustment operation is a state in which there is no load fluctuation, and the fluctuation in the direction in which the load on the system becomes lighter It is configured to determine which state is in a state where a light load fluctuation is occurring and a state where a heavy load fluctuation is occurring which is a fluctuation in a direction in which the load on the system becomes heavier. I understand that I can do it.

  More specifically, when V1b = V1c and / or V2b = V2c, it can be determined that there is no load fluctuation immediately after the tap switching, and when V1b <V1c and / or V2b <V2c. It can be determined that a light load fluctuation has occurred immediately after the tap switching. Further, when V1b> V1c and / or V2b> V2c, it can be determined that the heavy load fluctuation has occurred immediately after the tap switching. That is, by comparing primary voltages or secondary voltages measured at the second measurement timing and the third measurement timing, respectively, or by comparing primary voltages and secondary voltages, The load state of the system can be determined.

Also, the determination result of the load state immediately after the tap switching, the determination result of whether the voltage adjustment operation is a tap up or a tap down, the first primary voltage V1a and the third voltage shown in FIGS. From the relationship between the primary voltage V1c and the relationship between the first secondary voltage V2a and the third secondary voltage V2c, the cause of the reverse power flow in the SVR is the distribution line on the primary side of the SVR. When the distributed power supply is linked to the secondary distribution line of the SVR while being connected to the power substation, the following (a) 'to (f)' can be said.
(A) 'When the voltage adjustment operation is tap-up and there is no load fluctuation in the system immediately after the tap-up, the third primary voltage V1c is equal to the first primary voltage V1a, and the third The secondary voltage V2c is equal to the first secondary voltage V2a.
(B) 'When the voltage adjustment operation is tap reduction, and there is no load fluctuation in the system immediately after tap reduction, the third primary voltage V1c is equal to the first primary voltage V1a, and the third Secondary voltage V2c is lower than the first secondary voltage V2a.
(C) When the voltage adjustment operation is a tap-up and a light load fluctuation has occurred in the system immediately after the tap-up, the third primary voltage V1c is higher than the first primary voltage V1a. The third secondary voltage V2c is higher than the first secondary voltage V2a.
(D) 'If the voltage adjustment operation is a tap reduction and a light load fluctuation has occurred in the system immediately after the tap reduction, the third primary voltage V1c is higher than the first primary voltage V1a. The third secondary voltage V2c is lower than the first secondary voltage V2a.
(E) 'When the voltage adjustment operation is a tap-up and a heavy load fluctuation has occurred in the system immediately after the tap-up, the third primary voltage V1c is lower than the first primary voltage V1a. The third secondary voltage V2c is higher than the first secondary voltage V2c.
(F) 'If the voltage adjustment operation is a tap reduction and a heavy load fluctuation occurs immediately after the tap reduction, the third primary voltage V1c is lower than the first primary voltage V1a. The third secondary voltage V2c is lower than the first secondary voltage V2c.

Further, the determination result of the load state immediately after the tap switching, the determination result of whether the voltage adjustment operation is a tap-up or tap-down, the first primary voltage V1a and the third voltage shown in FIGS. From the relationship between the primary voltage V1c and the relationship between the first secondary voltage V2a and the third secondary voltage V2c, the cause of the reverse power flow in the SVR is the primary side of the SVR due to the system switching. (G) 'to (l)' below when the distribution line is disconnected from the power substation and the secondary distribution line is connected to another power supply substation I can say.
(G) 'When the voltage adjustment operation is tapping, and there is no load fluctuation immediately after tapping, the third primary voltage V1c is lower than the first primary voltage V1a, and the third The secondary voltage V2c is equal to the first secondary voltage V2a.
(H) 'When the voltage adjustment operation is tap reduction and there is no load fluctuation immediately after the tap reduction, the third primary voltage V1c is higher than the first primary voltage V1a, and the third The secondary voltage V2c is equal to the first secondary voltage V1c.
(I) When the voltage adjustment operation is a tap-up and a light load fluctuation occurs immediately after the tap-up, the third primary voltage V1c is lower than the first primary voltage V1a, 3 secondary voltage V2c is higher than the first secondary voltage V2a.
(J) 'When the voltage adjustment operation is tap reduction and a light load fluctuation occurs immediately after tap reduction, the third primary voltage V1c is higher than the first primary voltage V1a, 3 secondary voltage V2c is higher than the first secondary voltage V2a.
(K) ′ When the voltage adjustment operation is a tap-up and a heavy load fluctuation occurs immediately after the tap-up, the third primary voltage V1c is lower than the first primary voltage V1a, 3 secondary voltage V2c is lower than the first secondary voltage V2a.
(L) 'When the voltage adjustment operation is tap reduction, and a heavy load fluctuation occurs immediately after tap reduction, the third primary voltage V1c is higher than the first primary voltage V1a, 3 secondary voltage V2c is lower than the first secondary voltage V2a.

  A table summarizing the above results is shown in FIG. In FIG. 8, as shown in FIGS. 4 to 7, the third primary voltage V1c is equal to the first primary voltage V1a (a state in which there is no change in voltage before and after tap switching). Is represented by “0”, and a state in which the third primary voltage V1c is higher than the first primary voltage V1a (a state in which the voltage is increased after the tap switching than before the tap switching) is represented by “+”. A state in which the voltage V1c is lower than the first primary voltage V1a (a state in which the voltage has decreased after the tap switching than before the tap switching) is represented by “−”. A state in which the third secondary voltage V2c is equal to the first secondary voltage V2a (a state in which there is no voltage change before and after tap switching) is represented by “0”, and the third secondary voltage V2c is the first secondary voltage V2c. A state higher than the secondary voltage V2a (a state where the voltage has increased after the tap switching than before the tap switching) is represented by “+”, and the third secondary voltage V2c is lower than the first secondary voltage V2a ( “−” Indicates a state in which the voltage is lower than that before the tap switching after the tap switching. FIG. 8A shows a case where there is no load fluctuation in the system immediately after the voltage adjustment operation is performed during reverse power flow, and FIG. 8B is a diagram of the system immediately after the voltage adjustment operation is performed during reverse power flow. Shows the case where light load fluctuation occurred. FIG. 8C shows a case where a heavy load fluctuation has occurred in the system immediately after the voltage adjustment operation during reverse power flow.

  As described above, the determined load state of the system, the determination result of whether the voltage adjustment operation performed by the SVR is tap-up or tap-down, and the first measurement timing and the third measurement timing, respectively. There is a certain relationship between the measured result of comparison between the primary voltages (change in the primary voltage immediately after the tap switching) and the cause of the reverse power flow occurring in the SVR. Also, the determined load state of the system, the determination result of whether the voltage adjustment operation performed by the SVR is tap-up or tap-down, and the two measured at the first measurement timing and the third measurement timing, respectively. There is also a certain relationship between the comparison determination result between the secondary voltages (change in the secondary voltage immediately after the tap switching) and the cause of the reverse power flow generated in the SVR.

  Therefore, when the SVR performs voltage adjustment in the state where the reverse power flow is detected in the SVR, the first measurement timing and the tap that are set before the timing when the SVR tap is switched are switched. The SVR primary side voltage is set to the first primary voltage at the second measurement timing tb set immediately after the second measurement timing and at the third measurement timing tc set slightly later than the second measurement timing. Measuring the voltage, the second primary voltage, and the third primary voltage, and measuring the secondary voltage of the SVR as the first secondary voltage, the second secondary voltage, and the third secondary voltage, The comparison between the primary voltage of 2 and the third primary voltage and / or the comparison of the second secondary voltage and the third secondary voltage was performed, and from the comparison result, the SVR performed the voltage adjustment operation. Immediate load on the system A load state that determines whether the state is a state where there is no load variation, a light load variation where the load on the system is light, or a heavy load variation where the load on the system is heavy The voltage adjustment operation performed by the determination process and the SVR boosts the secondary voltage of the SVR when a power substation is connected to the primary side of the SVR and power flows in the forward direction through the SVR. A voltage adjustment operation determination process for determining whether the tap is to be switched up in a direction to become a tap-up or a tap-down to be switched in a direction opposite to the direction at which the tap is raised, a first primary voltage and a third primary voltage And / or a comparison between the first secondary voltage and the third secondary voltage, and a voltage change determination process at the time of tap switching for determining the relationship between the levels of the compared voltages and a load state determination process Size By comparing the determination result in the voltage adjustment operation determination process and the determination result in the voltage change determination process at tap switching with the determination requirements prepared in advance for these determination results, a reverse power flow occurs. The reason is that the distributed power supply is linked to the secondary distribution line of the SVR while the primary distribution line of the SVR is connected to the power substation, or the primary side of the SVR is changed by switching the system. It occurs in SVR by performing the reverse power flow cause determination process that determines whether the distribution line is disconnected from the power supply substation and the secondary distribution line is connected to another power supply substation. The cause of the reverse power flow can be accurately identified.

  The reverse power flow cause determination unit 27 shown in FIG. 2 determines the determination result by the load state determination unit, the determination result by the voltage adjustment operation determination unit 24, and the determination result by the voltage change determination unit 26 at tap switching. By comparing the results with the judgment requirements prepared in advance, the cause of the reverse power flow is that the automatic voltage regulator primary power distribution line is connected to the power substation. Whether the distributed power supply is linked to the distribution line on the secondary side, the distribution line on the primary side of the automatic voltage regulator is disconnected from the power substation by switching the system, and the distribution line on the secondary side is connected to the other It can be configured to determine whether it is connected to the power supply substation of the system.

More specifically, the determination result in the load state determination process, the determination result in the voltage adjustment operation determination process, and the determination result in the voltage change determination process at tap switching are any of the following (a) to (f): When the automatic voltage regulator is in a state where the distribution line on the primary side of the automatic voltage regulator is connected to the power substation, It can be determined that the distributed power supply is linked to the distribution line on the secondary side.
(A) Immediately after the automatic voltage regulator performs the voltage adjustment operation, it is determined that there is no load fluctuation in the system, and the third primary voltage is the first voltage when it is determined that the voltage adjustment operation is a tap-up. Is equal to the primary voltage and the third secondary voltage is determined to be equal to the first secondary voltage.
(B) Immediately after the automatic voltage regulator performs the voltage adjustment operation, it is determined that there is no load fluctuation in the system, and the third primary voltage is the first voltage in a state where it is determined that the voltage adjustment operation is a tap down. When the third secondary voltage is determined to be lower than the first secondary voltage.
(C) Immediately after the automatic voltage regulator performs the voltage adjustment operation, it is determined that a light load fluctuation has occurred in the system, and it is determined that the voltage adjustment operation is a tap-up, the third primary voltage is When it is determined that the third secondary voltage is higher than the first primary voltage and the third secondary voltage is higher than the first secondary voltage.
(D) The third primary voltage in a state where it is determined that the light load fluctuation has occurred in the system immediately after the automatic voltage regulator performs the voltage adjustment operation, and the voltage adjustment operation is determined to be a tap down. Is determined to be higher than the first primary voltage and the third secondary voltage is lower than the first secondary voltage.
(E) In a state where it is determined that a heavy load fluctuation has occurred in the system immediately after the automatic voltage regulator performs the voltage adjustment operation, and it is determined that the voltage adjustment operation is tapping, the third primary voltage is When it is determined that the third secondary voltage is lower than the first primary voltage and the third secondary voltage is higher than the first secondary voltage.
(F) In a state where it is determined that the heavy load fluctuation has occurred in the system immediately after the automatic voltage regulator performs the voltage adjustment operation, and the voltage adjustment operation is determined to be a tap down, the third primary When it is determined that the voltage is lower than the first primary voltage and the third secondary voltage is lower than the first secondary voltage.

In addition, the determination result in the load state determination process, the determination result in the voltage adjustment operation determination process, and the determination result in the voltage change determination process at the time of tap switching satisfy the following determination requirements (g) to (l): When applicable, the cause of reverse power flow is that the distribution line on the primary side of the automatic voltage regulator is disconnected from the power substation by switching the system, and the distribution line on the secondary side is connected to the power substation of the other system. It can be determined that it is connected to a place.
(G) Immediately after the automatic voltage regulator performs the voltage adjustment operation, it is determined that there is no load fluctuation in the system, and the third primary voltage is the first voltage in a state where it is determined that the voltage adjustment operation is tapping. And when the third secondary voltage is determined to be equal to the first secondary voltage.
(H) Immediately after the automatic voltage regulator performs the voltage adjustment operation, it is determined that there is no load fluctuation in the system, and it is determined that the voltage adjustment operation is a tap down, the third primary voltage is the first voltage And when the third secondary voltage is determined to be equal to the first secondary voltage.
(I) The third primary voltage in a state where it is determined that the light load fluctuation has occurred in the system immediately after the automatic voltage regulator performs the voltage adjustment operation, and the voltage adjustment operation is determined to be tapping. Is lower than the first primary voltage and the third secondary voltage is determined to be higher than the first secondary voltage.
(J) In a state where it is determined that a light load fluctuation has occurred in the system immediately after the automatic voltage regulator performs a voltage adjustment operation, and the voltage adjustment operation is determined to be a tap down, the third primary voltage is When it is determined that the third secondary voltage is higher than the first primary voltage and the third secondary voltage is higher than the first secondary voltage.
(K) The third primary voltage in a state in which it is determined that the heavy load fluctuation has occurred in the system immediately after the automatic voltage regulator performs the voltage adjustment operation and the voltage adjustment operation is determined to be a tap-up. Is determined to be lower than the first primary voltage and the third secondary voltage is lower than the first secondary voltage.
(L) In a state where it is determined that a heavy load fluctuation has occurred in the system immediately after the automatic voltage regulator performs the voltage adjustment operation, and the voltage adjustment operation is determined to be a tap down, the third primary voltage is When it is determined that the voltage is higher than the first primary voltage and the third secondary voltage is lower than the first secondary voltage.

  The power flow cause determination means 27 shown in FIG. 2 includes the determination result by the load state determination means 23, the determination result by the voltage adjustment operation determination means 24, and the determination result by the voltage change determination means 26 at tap switching. When any of the judgment requirements in (f) is met, the cause of reverse power flow in the automatic voltage regulator is that the distribution line on the primary side of the automatic voltage regulator is connected to the power substation. It is determined that the distributed power supply is linked to the distribution line on the secondary side of the automatic voltage regulator, the determination result by the load state determination means 23, the determination result by the voltage adjustment operation determination means 24, and the voltage change determination means at the time of tap switching. When the determination result of 26 corresponds to any of the determination requirements (g) to (l) above, the cause of the reverse power flow is the distribution line on the primary side of the automatic voltage regulator by switching the system Power substation Disconnected from, it may be configured to determine to be in the secondary side of the distribution line is connected to a power supply substation other strains.

  In the above embodiment, the first measurement timing ta is set to a timing before the timing at which the SVR performs tap switching. In general, a tap changer rotates a drive shaft by a motor when a tap change command is given, and a series of operations necessary to change the tap of the adjustment transformer while the drive shaft rotates by a predetermined angle. To do. Therefore, a certain time is required from when the tap switching command is given until when the tap is actually switched. The first measurement timing ta can be a timing at which a tap switching command is given to the tap switch 2B. The second measurement timing tb is set to a timing immediately after the SVR switches the tap. The third measurement timing tc is slightly delayed from the second measurement timing tb, and the difference between the second primary voltage V1b and the third primary voltage V1c and the second secondary voltage V2b. And a timing at which the difference between the second secondary voltage V2c can be clearly detected. The second measurement timing tb and the third measurement timing tc are appropriately set based on the result of actual measurement.

  The present invention relates to a distribution system in which distributed power sources such as solar power generation facilities and wind power generation facilities are linked, and when a reverse power flow occurs in an automatic voltage regulator, whether the cause is system switching or the distributed power source. Therefore, when the automatic voltage regulator causes a reverse power flow, the information for switching the operation mode of the automatic voltage regulator to a mode suitable for the system status can be accurately determined. Can get to. Therefore, by applying to an automatic voltage regulator installed in a distribution system to which distributed power sources are linked, the automatic voltage regulator can be appropriately operated to contribute to the stabilization of the system.

1 system power substation 2 automatic voltage regulator 3 substation switch 4 primary side distribution line 5 secondary side distribution line 6 other system distribution line 7 switch installed between other systems 10 current transformer DESCRIPTION OF SYMBOLS 11 Reverse power relay 12 Power reverse flow detection apparatus 13 Instrument transformer 14 Instrument transformer 15 Primary side voltage detection circuit 16 Secondary side voltage measurement circuit 17 1st A / D converter 18 2nd A / D conversion 19 Measurement command signal generation means 20 Microprocessor 22 Voltage measurement means 23 Load state determination means 24 Voltage adjustment operation determination means 26 Tap change voltage change determination means 27 Reverse power flow cause determination means

Claims (4)

For power distribution to determine the cause of reverse power flow when a reverse power flow that flows from the secondary side to the primary side occurs with a load-switchable automatic voltage regulator installed in the distribution system. In the method of determining the cause of reverse power flow in the automatic voltage regulator,
When the automatic voltage regulator performs voltage adjustment in a state where a reverse power flow is detected by the automatic voltage regulator, a timing set before the timing at which the tap of the automatic voltage regulator is switched is set. 1 measurement timing ta, a second measurement timing tb set immediately after the tap is switched, and a third measurement timing tc set slightly later than the second measurement timing. And measuring the primary voltage of the automatic voltage regulator as a first primary voltage, a second primary voltage and a third primary voltage, respectively, and measuring the secondary voltage of the automatic voltage regulator as a first secondary voltage. Measured as voltage, second secondary voltage and third secondary voltage,
A comparison between the second primary voltage and the third primary voltage and / or a comparison between the second secondary voltage and the third secondary voltage is performed. The load state of the system immediately after performing the adjustment operation is a state in which there is no load fluctuation, a light load fluctuation in which the system load is light, and a heavy load fluctuation in which the system load is heavy. A load state determination process for determining which one of them,
The automatic voltage regulator performs the voltage regulation operation when a power substation is connected to the primary side of the automatic voltage regulator and power flows in the forward direction through the automatic voltage regulator. A voltage adjustment operation determination process for determining whether the tap is to be switched in the direction in which the secondary side voltage of the regulator is to be boosted, or to be a tap down to switch the tap in the opposite direction to that when the tap is raised,
A comparison between the first primary voltage and the third primary voltage and / or a comparison between the first secondary voltage and the third secondary voltage is performed to determine a level relationship of the compared voltages. Voltage change judgment process at tap switching,
The determination result in the load state determination process, the determination result in the voltage adjustment operation determination process, and the determination result in the voltage change determination process at tap switching are collated with determination requirements prepared in advance for these determination results. The cause of the reverse power flow is that a distributed power source is connected to the secondary distribution line of the automatic voltage regulator in a state where the primary distribution line of the automatic voltage regulator is connected to a power substation. Is it because it was linked? The primary distribution line of the automatic voltage regulator was disconnected from the power substation by switching the system, and the secondary distribution line was connected to the power substation of another system Reverse power flow cause determination process to determine whether or not
A method for determining the cause of reverse power flow in an automatic voltage regulator for power distribution, characterized in that: The reverse flow cause determination process includes
(A) Immediately after the automatic voltage regulator performs the voltage adjustment operation, it is determined that there is no load fluctuation in the system, and the third primary voltage is the first voltage when it is determined that the voltage adjustment operation is a tap-up. When it is determined that the third secondary voltage is equal to the first secondary voltage and (b) the automatic voltage regulator performs a voltage regulation operation, there is no load fluctuation in the system. The third primary voltage is equal to the first primary voltage and the third secondary voltage is lower than the first secondary voltage in a state where it is determined that the voltage adjustment operation is a tap-down operation. (C) a state in which it is determined that the light load fluctuation has occurred in the system immediately after the automatic voltage regulator performs the voltage adjustment operation, and the voltage adjustment operation is determined to be a tap-up. And the third primary voltage is higher than the first primary voltage, When it is determined that the secondary voltage of 3 is higher than the first secondary voltage, (d) it is determined that the light load fluctuation has occurred in the system immediately after the automatic voltage regulator performs the voltage adjustment operation, In the state where the voltage adjustment operation is determined to be a tap reduction, it is determined that the third primary voltage is higher than the first primary voltage and the third secondary voltage is lower than the first secondary voltage. (E) in a state where it is determined that the heavy load fluctuation has occurred in the system immediately after the automatic voltage regulator performs the voltage adjustment operation, and the voltage adjustment operation is determined to be a tap-up, When it is determined that the third primary voltage is lower than the first primary voltage and the third secondary voltage is higher than the first secondary voltage; and (f) the automatic voltage regulator performs the voltage adjustment operation. It is determined that the heavy load fluctuation has occurred in the system immediately after being performed, and the voltage When the third primary voltage is determined to be lower than the first primary voltage and the third secondary voltage is determined to be lower than the first secondary voltage with the rectifying operation determined to be a tap down Furthermore, the cause of the reverse power flow is that a distributed power source is connected to the secondary distribution line of the automatic voltage regulator in a state where the primary distribution line of the automatic voltage regulator is connected to a power substation. It ’s determined that it ’s linked,
(G) Immediately after the automatic voltage regulator performs the voltage adjustment operation, it is determined that there is no load fluctuation in the system, and the third primary voltage is the first voltage when it is determined that the voltage adjustment operation is tapping. When it is determined that the third secondary voltage is lower than the primary voltage of 1 and the third secondary voltage is equal to the first secondary voltage, (h) immediately after the automatic voltage regulator performs the voltage adjustment operation, there is a load fluctuation in the system. The third primary voltage is higher than the first primary voltage, and the third secondary voltage is changed to the first secondary voltage in a state where it is determined that the voltage adjustment operation is a tap-down. When it is determined that they are equal, (i) immediately after the automatic voltage regulator performs the voltage adjustment operation, it is determined that the light load fluctuation has occurred in the system, and it is determined that the voltage adjustment operation is tapping. The third primary voltage is lower than the first primary voltage When it is determined that the third secondary voltage is higher than the first secondary voltage, (j) it is determined that the light load fluctuation has occurred in the system immediately after the automatic voltage regulator performs the voltage adjustment operation. And the third primary voltage is higher than the first primary voltage and the third secondary voltage is higher than the first secondary voltage in a state where it is determined that the voltage adjustment operation is a tap down. (K) in a state where it is determined that the heavy load fluctuation has occurred in the system immediately after the automatic voltage regulator performs the voltage adjustment operation, and the voltage adjustment operation is determined to be a tap-up. , When it is determined that the third primary voltage is lower than the first primary voltage and the third secondary voltage is lower than the first secondary voltage, and (l) the automatic voltage regulator operates the voltage adjustment It is determined that the heavy load fluctuation has occurred in the system immediately after When the third primary voltage is determined to be higher than the first primary voltage and the third secondary voltage is determined to be lower than the first secondary voltage with the adjustment operation determined to be a tap down In addition, the cause of the reverse power flow is that the distribution line on the primary side of the automatic voltage regulator is disconnected from the power supply substation by switching the system, and the distribution line on the secondary side is the power supply substation of the other system. Determining that it is connected to
The power reverse power flow cause determination method of the automatic voltage regulator for power distribution according to claim 1. Automatic voltage regulator for distribution that determines the cause of reverse power flow when a reverse power flow occurs from the secondary side to the primary side using a tap-switchable automatic voltage regulator installed in the distribution system In the reverse power flow cause determination device of
When the automatic voltage regulator performs voltage adjustment in a state where a reverse power flow is detected by the automatic voltage regulator, a timing set before the timing at which the tap of the automatic voltage regulator is switched is set. 1 measurement timing ta, a second measurement timing tb set immediately after the tap is switched, and a third measurement timing tc set slightly later than the second measurement timing. And measuring the primary voltage of the automatic voltage regulator as a first primary voltage, a second primary voltage and a third primary voltage, respectively, and measuring the secondary voltage of the automatic voltage regulator as a first secondary voltage. Voltage measuring means for measuring the voltage, the second secondary voltage and the third secondary voltage;
A comparison between the second primary voltage and the third primary voltage and / or a comparison between the second secondary voltage and the third secondary voltage is performed. The load state of the system immediately after performing the adjustment operation is a state in which there is no load change, a light load change that is a change in a direction in which the load on the system is light, and a direction in which the load on the system becomes heavy. Load state determination means for determining which state is in a state where a heavy load variation that is a variation is occurring;
The voltage adjustment operation performed by the automatic voltage regulator is a tap that switches the tap in the direction of boosting the secondary voltage of the automatic voltage regulator in a state where a power substation is connected to the primary side of the automatic voltage regulator. Voltage adjustment operation determination means for determining whether it is a tap-up or a tap-down switching the tap in the opposite direction to the tap-up time,
A comparison between the first primary voltage and the third primary voltage and / or a comparison between the first secondary voltage and the third secondary voltage is performed to determine a level relationship of the compared voltages. Voltage change determining means at tap switching;
By comparing the determination result by the load state determination unit, the determination result by the voltage adjustment operation determination unit, and the determination result by the voltage change determination unit at tap switching with the determination requirements prepared in advance for these determination results The cause of the reverse power flow is that the distributed power supply is linked to the secondary distribution line of the automatic voltage regulator in a state where the primary distribution line of the automatic voltage regulator is connected to the power substation. This is because the distribution line on the primary side of the automatic voltage regulator is disconnected from the power substation by switching the system, and the distribution line on the secondary side is connected to the power substation in the other system. A reverse power flow cause determination means for determining whether there is,
An apparatus for determining the cause of reverse power flow in an automatic voltage regulator for power distribution, comprising: The reverse power flow cause determining means is:
(A) Immediately after the automatic voltage regulator performs the voltage adjustment operation, it is determined that there is no load fluctuation in the system, and the third primary voltage is the first voltage when it is determined that the voltage adjustment operation is a tap-up. When it is determined that the third secondary voltage is equal to the first secondary voltage and (b) the automatic voltage regulator performs a voltage regulation operation, there is no load fluctuation in the system. The third primary voltage is equal to the first primary voltage and the third secondary voltage is lower than the first secondary voltage in a state where it is determined that the voltage adjustment operation is a tap-down operation. (C) a state in which it is determined that the light load fluctuation has occurred in the system immediately after the automatic voltage regulator performs the voltage adjustment operation, and the voltage adjustment operation is determined to be a tap-up. And the third primary voltage is higher than the first primary voltage, When it is determined that the secondary voltage of 3 is higher than the first secondary voltage, (d) it is determined that the light load fluctuation has occurred in the system immediately after the automatic voltage regulator performs the voltage adjustment operation, In the state where the voltage adjustment operation is determined to be a tap reduction, it is determined that the third primary voltage is higher than the first primary voltage and the third secondary voltage is lower than the first secondary voltage. (E) in a state where it is determined that the heavy load fluctuation has occurred in the system immediately after the automatic voltage regulator performs the voltage adjustment operation, and the voltage adjustment operation is determined to be a tap-up, When it is determined that the third primary voltage is lower than the first primary voltage and the third secondary voltage is higher than the first secondary voltage; and (f) the automatic voltage regulator performs the voltage adjustment operation. It is determined that the heavy load fluctuation has occurred in the system immediately after being performed, and the voltage When the third primary voltage is determined to be lower than the first primary voltage and the third secondary voltage is determined to be lower than the first secondary voltage with the rectifying operation determined to be a tap down Furthermore, the cause of the reverse power flow is that a distributed power source is connected to the secondary distribution line of the automatic voltage regulator in a state where the primary distribution line of the automatic voltage regulator is connected to a power substation. It ’s determined that it ’s linked,
(G) Immediately after the automatic voltage regulator performs the voltage adjustment operation, it is determined that there is no load fluctuation in the system, and the third primary voltage is the first voltage when it is determined that the voltage adjustment operation is tapping. When it is determined that the third secondary voltage is lower than the primary voltage of 1 and the third secondary voltage is equal to the first secondary voltage, (h) immediately after the automatic voltage regulator performs the voltage adjustment operation, there is a load fluctuation in the system. The third primary voltage is higher than the first primary voltage, and the third secondary voltage is changed to the first secondary voltage in a state where it is determined that the voltage adjustment operation is a tap-down. When it is determined that they are equal, (i) immediately after the automatic voltage regulator performs the voltage adjustment operation, it is determined that the light load fluctuation has occurred in the system, and it is determined that the voltage adjustment operation is tapping. The third primary voltage is lower than the first primary voltage When it is determined that the third secondary voltage is higher than the first secondary voltage, (j) it is determined that the light load fluctuation has occurred in the system immediately after the automatic voltage regulator performs the voltage adjustment operation. And the third primary voltage is higher than the first primary voltage and the third secondary voltage is higher than the first secondary voltage in a state where it is determined that the voltage adjustment operation is a tap down. (K) in a state where it is determined that the heavy load fluctuation has occurred in the system immediately after the automatic voltage regulator performs the voltage adjustment operation, and the voltage adjustment operation is determined to be a tap-up. , When it is determined that the third primary voltage is lower than the first primary voltage and the third secondary voltage is lower than the first secondary voltage, and (l) the automatic voltage regulator operates the voltage adjustment It is determined that the heavy load fluctuation has occurred in the system immediately after When the third primary voltage is determined to be higher than the first primary voltage and the third secondary voltage is determined to be lower than the first secondary voltage with the adjustment operation determined to be a tap down In addition, the cause of the reverse power flow is that the distribution line on the primary side of the automatic voltage regulator is disconnected from the power supply substation by switching the system, and the distribution line on the secondary side is the power supply substation of the other system. Is configured to determine that it is connected to,
The power reverse power flow cause determination device for an automatic voltage regulator for power distribution according to claim 3.

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