JPH10170554A - Transformer current measuring device of receiving and transforming station - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily measure current by setting an input signal gain to a transformer setting capacity that is initially set. SOLUTION: First, a current signal from a current transformer 3 being mounted on a transformer secondary side electric path 2 is converted into a signal that is suitable for an electronic circuit by an input detection means 4. In this case, the rated capacity of a transformer 1, where the transformer secondary side electric path 2 to be measured is connected, is set by a transformer rated capacity setting means 5, a rated current is obtained from the set rated capacity, and a gain that is optimum for the rated current is set as an initial setting by a gain-setting means 6. Then, after the initial setting, no complex control such as an auto-range-switching system is required since a range-setting machine does not function, thus enabling processing to be made easily. A signal whose gain is set is inputted to a current measurement means 7 and is converted to digital data, and the current of the transformer secondary side electric path 2 is measured digitally.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transformer current measuring device of a substation equipment for measuring a transformer current on a high voltage side or a low voltage side via a current transformer.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 2, a transformer current measuring device for a power receiving and transforming facility includes an input detecting means 11 for detecting a transformer current via a current transformer 10 and a current detected by the transformer. The measurement was performed by the measuring means 12. In this case, the input detection means 11 generally has a fixed gain.

[0003]

In recent years, ammeters have also been digitized, and accordingly, high-precision measurement and standardization of equipment have been pursued. In one direction, the current rating of the ammeter was conventionally designed according to the rated capacity of the transformer. However, for standardization, the current transformer with the rated current that matches the maximum rated capacity of the transformer used Is being selected. On the other hand, when the rated capacity of the transformer is small, an extremely small current is always measured as compared with the selected rated current of the current transformer, and there is a disadvantage that accuracy may decrease. Was. In order to solve the above-mentioned drawback, for example, in the case of using an A / D converter, a high-resolution A / D converter may be used, but it is costly.

There is also an auto-range switching system for switching to an optimum range according to an input level. If this system is used, accuracy is improved. There is a problem that the setting becomes complicated, and in particular, responsiveness to a severe input change before and after the range switching level deteriorates.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems, in which the gain setting is performed only at the initial setting by setting the rated capacity of the transformer, and the transformer current measurement of the substation equipment for easily and accurately measuring the current. It is intended to provide a device.

[0006]

In order to achieve this object, a current measuring apparatus according to the present invention is provided with an input detecting means for detecting a high-voltage or low-voltage side transformer current through a current transformer, and initialization. Transformer rated capacity setting means, gain setting means for setting an input signal gain by an initially set transformer setting capacity, and current measuring means for digitally converting a signal from the gain setting means and measuring current. Things.

[0007]

According to this configuration, a current signal from a current transformer is detected by an input detecting means, and the gain setting means optimizes the transformer rated capacity set by the transformer rated capacity setting means in an initial setting. The gain is initially set, and the measurement is performed as the transformer current digitally converted by the current measuring means while the measurement range based on the measurement gain based on the optimum gain remains fixed thereafter.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
It is explained along. In FIG. 1, 1 is a transformer, 2 is a secondary circuit of the transformer 1, 3 is a current transformer provided on the secondary circuit 2, and 4 is an input for detecting a current from the current transformer 3. Detecting means, 5 is a transformer rated capacity setting means of the transformer 1, 6 is gain setting means for setting an optimum gain by the transformer capacity setting means 5, and 7 is a digital conversion of a signal from the gain setting means 6. It is a current measuring means for measuring current.

The operation of the current measuring device configured as described above will be described with reference to FIG. First, a current signal from the current transformer 3 attached to the transformer secondary-side electric circuit 2 is converted into a signal suitable for an electronic circuit by the input detection means 4. Here, the rated capacity of the transformer 1 to which the transformer secondary-side electric circuit 2 to be measured is set by the transformer rated capacity setting means 5 is set, the rated current is obtained from the set rated capacity, and the gain setting means 6 is set. Thus, the optimum gain setting for this rated current is performed as an initial setting. Since the range setting function does not work after the initial setting, complicated control such as the auto-range switching method is not required, and the processing is facilitated. This gain-set signal is input to the current measuring means 7,
The digital conversion is performed, and the current of the transformer secondary circuit 2 is digitally measured.

In the case of a fixed gain in which no gain is set by the rated current obtained by the transformer rated capacity setting means 5, if the rated current is much smaller than the rated current at which the fixed gain has an optimum value, the input current is inevitable. In this case, measurement is performed at a low range, and the accuracy is reduced.

The input data to the gain setting means 6 is the transformer rated capacity by the transformer rated capacity setting means 5, but may be the transformer rated current setting means.

[0012]

As described above, in the transformer current measuring apparatus of the power receiving and transforming equipment according to the present invention, it is assumed that the current transformer is limited to one type during the standardization of the rated current when the current transformer is used. However, since one model can be used for measurement in various measurement ranges, standardization can be performed without deteriorating performance, which is advantageous in terms of cost.At some point, the transformer was replaced with one with a different rated capacity Even if it is not necessary to change the measurement range, it is sufficient to change the setting of the rated capacity of the transformer. An object of the present invention is to realize an excellent current measuring device that can set a range and can easily and accurately measure a current of an electric circuit of a substation facility. Therefore, since the measurement range remains fixed after the initial setting, in the range switching control according to the input level, such as the auto-range switching method, the complexity of the input level determination processing and the gain setting accompanying the range switching is complicated. Control is not required, processing is easy, and even for severe input changes around the range switching level,
It has excellent effects such as not reducing the responsiveness.

[Brief description of the drawings]

FIG. 1 is a block diagram of a transformer current measuring device of a substation facility according to an embodiment of the present invention.

FIG. 2 is a block diagram of a conventional transformer current measuring device of a power receiving and transforming facility.

[Explanation of symbols]

 3 Current transformer 4 Input detection means 5 Transformer rated capacity setting means 6 Gain setting means 7 Current measurement means

Claims (2)

[Claims] An input detecting means for detecting a high voltage or low voltage side transformer current through a current transformer, a transformer rated capacity setting means for initial setting, and an input based on the set transformer rated capacity. A transformer current measuring device of a substation facility, comprising: gain setting means for setting a gain of a signal; and current measuring means for digitally converting a signal from the gain setting means and measuring a current. 2. A transformer current measuring device for a power receiving and transforming facility according to claim 1, wherein said transformer rated capacity setting means is a transformer rated current setting means.