JP2009117508A - Tap position determining device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tap position determining device capable of easily determining the current position of a tap from outside a transformer without newly constructing a circuit, a mechanism, etc., in the transformer. <P>SOLUTION: The tap position determining device includes a primary-side CT 14 measuring a primary-side current of the transformer, a secondary-side CT 16 measuring a secondary-side current of the transformer, a waveform acquisition unit 20 which acquires waveforms of the currents at a predetermined time measured by the primary-side CT 14 and secondary-side CT 16 at the same time, an arithmetic unit 25 which computes an average value of effective values of the waveforms acquired by the waveform acquisition unit 20, and a determining unit 28 which determines the tap position of the transformer from the ratio of the primary-side average value to the secondary-side average value computed by the arithmetic unit 25. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a tap position determination device, and more particularly to a tap position determination device that can determine the tap position of a transformer during power transmission without opening the top cover of the transformer and without causing a power failure.

  As a method of confirming the tap position of the transformer during power transmission, a method of opening the upper lid of the transformer by live line proximity work and visually confirming the tap switching plate is employed. However, since this method approaches the high-voltage line when opening the upper lid of the transformer, the risk is high. Moreover, since the work is performed with the top cover of the transformer opened, there is a risk that foreign matter or the like may be mixed inside the transformer.

  On the other hand, in Patent Document 1, in order to be able to monitor the tap position of the transformer at a remote place, the tap display shaft linked to the tap position and the rotating shaft of the variable resistor are connected, and both ends of the resistor of the variable resistor are connected. A technology that applies a reference voltage to the resistor, transmits the potential difference between one of the terminals of the resistor and the movable contact attached to the rotating shaft of the variable resistor, and reproduces the tap position by the potential difference transmitted at a remote location. It is disclosed.

  Further, in Patent Document 2, a tap switching transformer under load in which the tap position of the transformer is detected by sequentially reading the output from a multi-switching dial switch that is linked to the tap switching operation of the tap switching transformer under load. Monitoring the operating state of the tap changer driving tap changer of the on-load tap changer transformer, and updating the detected tap position based on the read dial switch output during the active period A tap position detecting device for an on-load tap switching transformer that prohibits the above is disclosed.

  Further, Patent Document 3 discloses a drive shaft up to an upper limit tap position and a lower limit tap position provided in the SVR in order to solve the difficulty of confirming the tap position display due to contamination of the insulating oil of the automatic voltage regulator (SVR). An operation state input unit for taking in the operation state of the first and second switches that define the rotation operation range of the first switch and the third switch that defines the rotation operation of the drive shaft at the time of reverse feeding corresponding to the current tap position And a determination unit that analyzes the captured switch operating state using a logical operation means to determine a tap position, and a display unit that displays an analysis result of the determination unit, and a current automatic voltage regulator A tap position determination display device is disclosed.

  In the above Patent Documents 1 to 3, when the tap position is changed, it is interlocked with the tap position, for example, Patent Document 1 is a tap display axis that is interlocked with the tap position, and Patent Document 2 is a multi-switching system that is interlocked with the tap switching operation. In the dial switch, Patent Document 3, the first and second switches that define the rotational operation range of the drive shaft up to the upper limit tap position and the lower limit tap position and the rotation operation of the drive shaft at the time of reverse feeding corresponding to the current tap position. A third switch is used.

JP-A-6-28593 Japanese Patent Publication No. 7-58654 JP 2006-179680 A

  As described above, all of the techniques disclosed in Patent Documents 1 to 3 use a technique that works in conjunction with the change of the tap position. Therefore, although it is safe without opening the top cover of the transformer, it is necessary to construct a new circuit, mechanism or the like for confirming or determining the current tap position. Accordingly, the cost of the transformer is increased accordingly, and since the mechanism and the like are complicated, it is undeniable that the probability of failure of the device for determining the tap position increases with aging of the used parts.

  The present invention has been made in view of the above problems, and its purpose is to easily determine the current tap position from the outside of the transformer without newly constructing a circuit or a mechanism in the transformer. It is in providing the tap position determination apparatus which can do.

  Based on the principle of the transformer, the inventors can determine the winding ratio by measuring the voltage or current on the primary side and the secondary side at the same time, and on the primary side, that is, on the high voltage side, Focusing on the fact that current measurement can be easily performed by using a flowmeter, the present invention has been achieved.

  In order to achieve the above object, the tap position determination device according to claim 1 has a built-in tap switching plate for switching a tap of a transformer, and the voltage on the secondary side is boosted or lowered by switching the tap. In the tap position determination device for determining the position of the tap of the transformer, primary current measuring means for measuring the current on the primary side of the transformer, and secondary current for measuring the current on the secondary side of the transformer A measurement means; a waveform acquisition section for acquiring a waveform of a current for a predetermined time simultaneously measured by the primary side current measurement means and the secondary side current measurement means; and an average of effective values of the waveforms acquired by the waveform acquisition section A calculation unit that calculates a value, and a determination unit that determines a tap position of the transformer based on a ratio between the average value on the primary side calculated by the calculation unit and the average value on the secondary side. Special To.

  By adopting such a configuration, the waveform of the current flowing through the primary and secondary wires of the transformer is acquired at the same time to determine the average value of each effective value, the average value of the primary side and the average of the secondary side By obtaining the turns ratio of the transformer by the ratio with the value, the current tap position of the transformer can be easily determined. Therefore, it is not necessary to perform a dangerous operation of opening the upper lid of the transformer, and it is not necessary to newly construct an additional circuit or mechanism.

  As described in claim 2, two of the secondary current measuring means are installed, and the average value of the secondary side is the sum of the respective average values measured by the two secondary side measuring means. It is characterized by being. Therefore, since the current flowing through the secondary-side electric wire is measured by the two current measuring means, it is possible to reduce the influence of measurement error and the like. Further, the present invention is applicable even when the secondary side current must be measured at two locations in principle, such as a transformer that distributes power by a single-phase three-wire system.

  As described in claim 3, the average value of the primary side current and the average value of the secondary side current are measured every 5 to 15 sets of 10 waves as one set after measurement is started. It is the average of the average value of. These conditions are determined based on experiments. If the waveform of the current acquired according to these conditions is processed, the position of the tap can be determined with sufficient accuracy.

  According to a fourth aspect of the present invention, the primary side current measuring means is a high voltage current transformer, and the secondary side current measuring means is a low voltage current transformer. It is possible to easily acquire the current waveform on the secondary side at low cost.

  As described in claim 5, the high-voltage current transformer is attached to the front end of an insulating Yatco and is detachable from the primary side electric wire of the transformer by a lever at hand. The side current transformer can be safely and easily attached to the primary wire of the transformer.

  According to the tap position determination device of the present invention, the waveform of the current flowing through the primary and secondary wires of the transformer is simultaneously obtained to obtain the average value of each effective value, the average value of the primary side and the secondary side By obtaining the winding ratio of the transformer by the ratio to the average value of the current value, it is possible to easily determine the current transformer tap position. Therefore, it is not necessary to perform a dangerous operation of opening the upper lid of the transformer, and it is not necessary to newly construct an additional circuit or mechanism.

  Embodiments of the present invention will be described in detail below with reference to the drawings. The present invention is not limited to the embodiments described below.

(First embodiment)
FIG. 1 is a schematic configuration diagram of a tap position determination device according to the present invention. The tap position determination device 10 includes a main body 12, a primary side CT (current transformer) 14 that is a primary side current measurement unit, and a secondary side CT 16 that is a secondary side current measurement unit. The main body 12 stores the waveform acquisition unit 20, the calculation unit 25, the determination unit 28, and the recording unit 30, and may include a display unit (not shown) as necessary. The computing unit 25 is divided into a first computing unit 22, a second computing unit 24, and a third computing unit 26, each of which plays a role of computation. Further, the main body unit 12 and the primary side CT 14 and the secondary side CT 16 are respectively connected by cables 18, and are configured such that current waveforms measured by each CT are separately input to the waveform acquisition unit 20. .

  The primary side CT14 is a high voltage current transformer, and the secondary side CT16 is a low voltage current transformer. This makes it possible to easily acquire the primary and secondary current waveforms at a low cost. Primary side CT14 is attached to the primary side electric wire of a transformer using an insulating Yatco as will be described later. By operating the operating lever at hand, this insulating Yatco can open and close the gripping metal fitting at the tip, and can be safely attached to the primary side of the transformer. Secondary side CT16 is attached to the secondary side electric wire of a transformer by manual work, without using an insulating Yatco etc.

  The cable 18 connects each CT and the waveform acquisition unit 20, and when there are a plurality of secondary side CTs 16, each is connected by the cable 18. In addition, since primary side CT14 is attached to the primary side electric wire of the transformer to which the high voltage is applied as mentioned above, sufficient insulation measures are taken for the cable 18 so as not to cause an electric shock.

  The waveform acquisition unit 20 acquires the primary side current waveform and the secondary side current waveform of the transformer measured by the primary side CT 14 and the secondary side CT 16, and these current waveforms are taken in as a function of time. The waveform acquisition unit 20 may be provided with a storage function, an averaging processing function, and the like.

  The first calculation unit 22 of the calculation unit 25 calculates the effective value (RMS) of the current waveform taken in by the waveform acquisition unit 20 for each of a plurality of continuous waveforms, and calculates an average value for a predetermined number of waveforms. It is to calculate. That is, the effective value of each of n consecutive waveforms taken from the start of measurement is calculated, and the average value is calculated by taking n as a set. The second calculation unit 24 calculates m sets of average values in which the average values calculated by the first calculation unit 22 are continuous. The 3rd calculating part 26 calculates the turns ratio of a transformer based on the preset formula based on the average value calculated by the 2nd calculating part 24. FIG.

  The determination unit 28 determines the tap position based on the result calculated by the third calculation unit 26. The recording unit 30 records the calculation results of the first calculation unit 22, the second calculation unit 24, and the third calculation unit 26 as necessary. In addition, you may display the determination result in the determination part 28 by a display part (not shown) as needed. The content of the display can be a winding ratio calculated by the third calculation unit 26, a tap value based on this winding ratio, and the like. Furthermore, you may comprise so that various information may be displayed as needed. In the present embodiment, as described in detail below, when the frequency of the current waveform is 50 Hz, n is 10 and m is 5 to 15, and when the frequency is 60 Hz, n is 12 and m is 5 to 5. It was set to 15.

  FIG. 2 is an explanatory diagram of the determination method of the tap position determination device of the present invention. The measurement of the primary side current waveform and the secondary side current waveform is started at the same time, and the calculation process is simultaneously performed. First, the primary side current measurement will be described. The primary side current waveform is acquired by the waveform acquisition unit 20 by the primary side CT 14. In FIG. 2, a current waveform acquired in one second from the start of measurement is indicated by reference numeral 42.

  The waveform 42 is divided every first 10 waves, that is, into five sections of 200 msec on the time axis, and the average value RMS1, RMS2,... RMS5 of each section is calculated by the first calculation unit 22. Specifically, RMS1 is an average value of the effective values of the first 10 waves, and the effective value is calculated for each of the waves. Similarly, RMS2 is an average value of effective values of the next 10 consecutive waves. After RMS1, RMS2,... RMS5 are obtained in this way, the average value thereof is calculated by the second calculation unit 24.

  As can be seen from the above description, if the waveform acquisition time is 1 second, when n is 10, m is 5, but m is 5 to 15, that is, the measurement time is set to 1 to 3 seconds. It is possible. The optimum n and m may be determined while observing the acquired current waveform. For example, if m is set to a small value, the measurement time can be shortened, but the accuracy of determination may deteriorate due to the influence of errors and the like. On the other hand, if m is set large, the accuracy of determination may deteriorate due to the influence of load fluctuations.

  The secondary side current measurement is performed in the same manner as described above. The secondary side current waveform is acquired by the waveform acquisition unit 20 by the secondary side CT16. In FIG. 2, the acquired current waveform is indicated by reference numeral 44. The current waveform 44 is acquired for 1 second from the start of measurement.

  The waveform 44 is divided into first 10 waves, that is, five sections of 200 milliseconds, and the average value RMS1, RMS2,... RMS5 of each section is calculated by the first calculation unit 22. Specifically, RMS1 is an average value of the effective values of the first 10 waves, and the effective value is calculated for each of the waves. Similarly, RMS2 is an average value of effective values of the next 10 consecutive waves. After RMS1, RMS2,... RMS5 are obtained in this way, the average value thereof is calculated by the second calculation unit 24.

  The average value calculated | required above is the intensity | strength of the electric current which flows through each electric wire, The calculation of winding ratio is performed in the 3rd calculating part 26 using the average value calculated in said 2nd calculating part 24. FIG. Here, the winding ratio is the ratio of the number of primary windings and the number of secondary windings of the transformer, and the relational expression between the winding ratio and the average value obtained above is: As shown in FIGS. 3, 6, and 7, which will be described later, it is given by the ratio between the average value on the primary side and the average value on the secondary side. Therefore, the third calculation unit 26 performs calculation based on these calculation formulas in order to obtain the winding ratio. When it is necessary to measure the current intensity of two wires with respect to the secondary side wires, two secondary side CTs 16 are prepared, and the secondary current waveform is acquired by each secondary side CT 16 and calculated. To calculate the current intensity of each wire.

  After the winding ratio is calculated by the third calculation unit 26, the determination of the tap position is performed by the determination unit 28. That is, the tap position is determined by converting the winding ratio into the tap value, and is specifically obtained as follows. The tap value 6600 corresponds to the ratio between the standard value of the primary side voltage of 6600 V and the secondary side standard value of 105 V, that is, the winding ratio is 62.858. Therefore, if the winding ratio obtained by the third calculation unit 26 is n, the tap value is determined as n / 62.858 × 6600. Therefore, the winding ratio n is calculated based on the average value of the primary side and the secondary side calculated by the third calculation unit 26, and the tap value is obtained by substituting it into the above formula, and the tap position is determined. It becomes.

  In addition, about the result calculated by the 1st calculating part 22, the 2nd calculating part 24, and the 3rd calculating part 26, it is recorded on the recording part 30 as needed, and it is comprised so that it can refer later. it can.

  FIG. 3 is a conceptual diagram of application of the tap position determination device of the present invention when two transformers 32 and 34 having the same rating are V-connected. FIG. 3A shows a case where the secondary CT16 is measured with two units, and FIG. 3B shows a case where the secondary CT16 is measured with one unit. The case where measurement is performed with one unit and the case where measurement is performed with two units is limited, for example, where the secondary CT 16 can be mounted, and when only one unit is mounted, FIG. 3B is applied. To do.

  In FIG. 3, Ia, Ib, and Ic are the intensity | strengths of the electric current which each flow through the R phase of the primary side electric wire, S phase, and T phase. I1, I2, and I3 are the intensities of currents flowing through the R-phase, S-phase, and T-phase of the secondary-side electric wire, respectively. I2 'is the intensity of the current flowing only through the S-phase transformer 34 in which the two transformers 32 and 34 are connected with respect to the secondary side.

  The winding ratio n is given by n = (I2 ′ + I3) / Ic (FIG. 3A), n = 2 · I3 / Ic (FIG. 3B), and I3, Ic, and I2 ′ are the second values. The calculation unit 24 calculates, and the third calculation unit 26 determines the winding ratio n.

  FIG. 4 is a schematic explanatory diagram of measurement by the tap position determination device of the present invention. FIG. 4A shows a case where the secondary side of the transformer is branched, and FIG. 4B shows a case where the transformer is not branched. A transformer 34 is installed on the utility pole 50, and a primary side electric wire 56 and a secondary side electric wire 58 are extended from the transformer 34. The primary side electric wire is connected to the high voltage pull-down electric wire 52 via the high voltage cutout 54. The secondary side electric wire 58 is connected to the load side.

  While holding the main body 12, the worker M installs the primary side CT 14 on the primary side electric wire 56 or the high voltage pull-down electric wire 14 and installs the secondary side CT 16 on the secondary side electric wire 58. Here, as described above, the primary side CT 14 is attached to the distal end of the insulating Ytco 48, and the gripping metal fitting at the distal end is opened and closed by operating the operating lever at hand, whereby the primary side electric wire 56 or the high-voltage pulling electric wire is opened. 52 can be safely attached. In addition, secondary side CT16 is attached manually by the secondary side electric wire of a transformer, without using an insulating Yatco etc. A difference between FIGS. 4A and 4B is the installation position of the secondary CT 16. The place where the secondary electric wire 58 is attached is limited by the presence or absence of branching.

  FIG. 5 shows one determination example. It is a tap display of the transformer which carried out the V connection shown in FIG. The vertical axis represents the tap value, and the horizontal axis represents the elapsed time from the start of measurement. It can be seen that the judgment value varies depending on the load fluctuation of the transformer, but does not belong to the two tap values, and the tap position is correctly judged.

(Second Embodiment)
The tap value determination apparatus of the present invention can be applied to cases other than the above-described V connection. For example, FIG. 6 is an application conceptual diagram in the case of applying to the three-phase transformer 40 according to the second embodiment. The main body 12, the primary side CT14, and the secondary side CT16 are the same as those described in the first embodiment. FIG. 6A shows a case where the tap strength is determined by measuring the strength of the current flowing through one electric wire on the primary side and two electric wires other than the phase on the secondary side. FIG. 5B shows a case where tap determination is made by measuring the intensity of the current flowing through the electric wire of one phase on the primary side and the electric wire of that phase on the secondary side.

  In FIG. 6, Ia, Ib, and Ic are the intensity | strengths of the electric current which each flow through the R phase, S phase, and T phase of a primary side electric wire. I1, I2, and I3 are the intensities of currents flowing through the R-phase, S-phase, and T-phase of the secondary-side electric wire, respectively. The winding ratio n is n = (I1 + I2) / Ic = (I1 + I3) / Ib = (I2 + I3) / Ia (FIG. 6A), or n = I1 / Ia = I2 / Ib = I3 / Ic (FIG. 6). Using the average values I1, I2, I3, I1, I2, and I3 given by (b)) and calculated by the second calculation unit 24, the third calculation unit 26 determines the winding ratio n. Then, the determination unit 28 determines the tap position. The method for obtaining the average value on the primary side and the secondary side is the same as in the first embodiment.

(Third embodiment)
FIG. 7 is an application conceptual diagram according to the third embodiment when power is distributed by a single transformer 60 in a single-phase three-wire system. The main body 12, the primary side CT14, and the secondary side CT16 are the same as those described in the first embodiment. In this case, two secondary CTs 16 are necessarily required, and the strengths Ia, I1 and I2 of the currents flowing through the primary side wires and wires other than the secondary side neutral wires are measured, and n = (I1 + I2) / A winding ratio n is obtained from Ia. The method for obtaining the average value on the primary side and the secondary side is the same as in the first embodiment, and the tap position can be correctly determined in the third embodiment.

  Note that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, the calculation unit is configured by three calculation units, but may be configured such that all calculations are performed by one calculation unit.

It is a schematic block diagram of the tap position determination apparatus of this invention. It is explanatory drawing which shows the determination method of the tap position determination apparatus of this invention. It is explanatory drawing at the time of applying the tap position determination apparatus of this invention to the transformer connected to V connection. It is a schematic explanatory drawing of the measurement by the tap position determination apparatus of this invention. It is an example of the result determined using the tap position determination apparatus of this invention. It is explanatory drawing in the case of applying the tap position determination apparatus of this invention to a three-phase transformer. It is explanatory drawing at the time of applying the tap position determination apparatus of this invention to a single phase 3 wire type transformer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Tap position determination apparatus 12 Main-body part 14 Primary side CT (Primary side electric current measurement means)
16 Secondary CT (secondary current measuring means)
20 waveform acquisition unit 25 calculation unit 28 determination unit 30 recording unit 42 primary current waveform 44 secondary current waveform

Claims (5)

In the tap position determination device for determining the position of the tap of the transformer, the tap switching plate for switching the tap of the transformer is built in, and the voltage on the secondary side is boosted or lowered by switching the tap.
Primary-side current measuring means for measuring the primary-side current of the transformer;
Secondary-side current measuring means for measuring the secondary-side current of the transformer;
A waveform acquisition unit for acquiring a waveform of a current of a predetermined time measured simultaneously by the primary side current measurement unit and the secondary side current measurement unit;
A calculation unit for calculating an average value of effective values of the waveforms acquired by the waveform acquisition unit;
A tap position determination device, comprising: a determination unit that determines a tap position of the transformer based on a ratio between the average value on the primary side calculated by the calculation unit and the average value on the secondary side.   The secondary side current measuring means is installed in two units, and the average value on the secondary side is the sum of the average values measured by the two secondary side measuring means. The tap position determination apparatus according to 1.   The average value on the primary side and the average value on the secondary side are averages of average values for every 5 to 15 sets of 10 waves that are one set after the start of measurement. The tap position determination apparatus according to claim 1 or 2.   The tap position according to any one of claims 1 to 3, wherein the primary current measuring means is a high voltage current transformer, and the secondary current measuring means is a low voltage current transformer. Judgment device.   The tap position determination device according to claim 4, wherein the high-voltage current transformer is attached to a distal end portion of an insulating Yatco and is attachable to and detachable from a primary side electric wire of the transformer by an operating lever at hand.

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