JPH0843447A - Method for calibrating optical fiber type ct - Google Patents

Abstract

PURPOSE:To improve measurement accuracy by providing a calibration signal generation part at an optical fiber type control transformer(CT). CONSTITUTION:When a test mode is selected by pressing a calibration button 21, a calibration signal, for example a light signal corresponding to AC5A is generated by a calibration signal generation part inside CT1A for detection and is inputted to an output part body 2A via an optical fiber cable 4. The inputted light signal (AC5A) is converted to an electrical signal by a photoelectric converter incorporated in the body 2A and AC5A is obtained from an AC output terminal 12 or a signal equivalent to for example DC100mV (equivalent to AC5A) is obtained from a DC output terminal 13, but the light signal is attenuated due to the error peculiar to light transmission. For compensating the amount of attenuation, a compensation dial 22 is rotated to determine the amount of AC amplification. For example, assuming that the test mode is selected and 97mV is outputted from the DC output terminal 13, the dial 22 is rotated while monitoring a voltmeter connected to the DC output terminal 13 to adjust the amount of amplification until the value reaches 100mV.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fiber optic CT calibration method for accurately detecting a high voltage current in power analysis and harmonic analysis.

[0002]

2. Description of the Related Art For example, in order to perform electric power measurement, a low-voltage electric power analyzer for measuring by a two-power meter method is used. When it is applied to the measurement of three-phase power, for example, CT for high-voltage current detection (optical fiber CT) is applied to the R and T phases, respectively.
Is set, and power measurement codes are set for the R phase, S phase, and T phase, respectively.

The high-voltage side power measurement is usually performed by combining a low-voltage power analyzer with a high-voltage current detection CT capable of measuring high-voltage current and its related device. FIG.
Shows the measurement status of three-phase power on the high voltage side. The state of setting on the T-phase side is similar to that on the R-phase side, and is not shown.

In FIG. 3, reference numeral 1 is a CT for detection (optical fiber CT), 2 is a main body of an output section, and 3 is a power analyzer.

In the figure, 4 is an optical fiber cable, 5 is an optical fiber connector (CT1 for detection).
), 6 is a current transformer, 7 is a range selector switch, and 8 is an opening / closing lever.

In the figure, 9 is an optical fiber connector (attached to the output unit main body 2), and 10 is AC100.
V input inlet, 11 is a power switch, 12 is an AC output terminal, 13 is a DC output terminal, and 14 is a connection cable.

Further, in the figure, 15 is a current input terminal, 15-1 is for R phase, 15-2 is for T phase, 1
6 is a voltage input terminal.

Further, in the figure, 17 is a power supply code and voltage measurement code (power measurement code), and 18 is a code 1.
Clip 7 is, 19 is PT, and 20 is a high voltage busbar.

The CT1 for detection is clamped on the high voltage bus bar 20 to take in a high voltage current. At this time, the range changeover switch 7 of the detecting CT 1 is set according to the magnitude of the line current flowing through the high voltage bus bar 20. The detected current is CT1 for detection
It is output as an optical signal through an EO converter (electrical signal-optical signal converter) built in the inside, and is input to the output unit main body 2 via the connector 9 by transmission by the optical fiber cable 4.

Since the output section main body 2 has a built-in OE converter (optical signal-electrical signal converter), the output becomes an electric signal, which is input to the power analyzer 3 via the connection cable 14.
The state becomes measurable.

As described above, the optical fiber cable 4 having excellent performance such as insulation is used in the transmission system for measuring the current flowing through the high-voltage bus 20, but there are error factors peculiar to the optical transmission, and signals are input and output. There was a problem in that precise measurements could not be made because they did not match.

That is, the degree of bending of the optical fiber cable 4 and the optical attenuation due to the adhesion of oil and dust on the optical fiber connecting connectors 5 and 9 are error factors, and these are not constant depending on the site of use, so they are managed. Was difficult.

Therefore, if the current signal input to the power analyzer 3 is significantly different from the true value, the accuracy of power measurement is affected, and it becomes necessary to correct the measured value after the measurement.

[0014]

In the power measurement using the conventional optical fiber type CT as described above, the optical fiber cable 4 is used, but there is an error factor peculiar to the optical transmission, and the signals are matched at the input and the output. However, there is a problem that precise measurement cannot be performed.

The present invention has been made to solve the above-mentioned problems, and an object thereof is to obtain a calibration method for an optical fiber CT which can improve the accuracy of measurement.

[0016]

A method for calibrating an optical fiber type CT according to claim 1 of the present invention is an optical fiber type C.
The step of generating a calibration signal in the test mode by the calibration signal generator built in T, and the adjustment of the signal sent through the optical fiber cable by the correction unit built in the output unit body to be the same as the calibration signal. And steps.

In the optical fiber CT calibrating method according to claim 2 of the present invention, the calibrating signal generating unit calibrates a calibration button for switching between a test mode and a measurement mode, and oscillates to generate a predetermined alternating current in the test mode. A circuit and an EO converter for converting the predetermined AC current into an optical signal, and the correction unit includes an OE converter for converting the optical signal into an AC current, and the converted AC current. And an amendment dial for adjusting the amplification amount of the AC amplification circuit.

[0018]

The optical fiber CT according to claim 1 of the present invention
In the calibration method, the step of generating a calibration signal in the test mode by the calibration signal generator incorporated in the optical fiber type CT and the signal sent through the optical fiber cable by the compensator incorporated in the output unit main body are used as the calibration signal. And the step of adjusting so as to be the same as, the accuracy of measurement can be improved.

In the optical fiber CT calibrating method according to claim 2 of the present invention, the calibrating signal generating section generates a calibrating button for switching between a test mode and a measuring mode, and a predetermined alternating current in the test mode. An oscillation circuit and an EO converter that converts the predetermined AC current into an optical signal, and the correction unit includes an OE converter that converts the optical signal into an AC current, and the converted AC. Since the AC amplification circuit that amplifies the current and the correction dial that adjusts the amplification amount of the AC amplification circuit are included, the accuracy of measurement can be easily improved.

[0020]

【Example】

Example 1. An embodiment of the present invention will be described with reference to FIGS. 1 is a plan view showing a CT for detection and an output unit main body according to Embodiment 1 of the present invention, and the optical fiber cable 4 to DC output terminal 13 are exactly the same as those of the conventional device. The power analyzer 3 is the same as the conventional one, and the same reference numerals in the respective drawings indicate the same or corresponding portions.

In FIG. 1, 1A is a detection CT (optical fiber CT), 2A is an output body, and 21 is a detection CT.
Calibration button on the grip of 1A, 22 is the output unit main body 2A
Is a correction dial, reference numeral 23 is a button for locking the correction dial 22 with a specific instruction value, and reference numeral 24 is a correction dial value scale.

In the first embodiment, the calibration button 21 is a push button type, and is an alternating setting type in which the test mode is pressed once and the measurement mode is pressed again. When the test mode is entered, a calibration signal, for example, an optical signal corresponding to AC5A is generated from the inside of the CT1A for detection and is input to the output unit main body 2A via the optical fiber cable 4.

The input optical signal (AC5A) becomes an electrical signal through the OE converter incorporated in the output unit main body 2A,
From the AC output terminal 12 of the output unit main body 2A to AC5A, and from the DC output terminal 13 of, for example, DC100 mV (AC5A
Corresponding signal is obtained.

However, as described in the description of the conventional example, the optical signal is attenuated by the error peculiar to the optical transmission. In order to correct the attenuated amount, the correction dial 22 attached to the output unit main body 2A is turned to determine the AC amplification amount. For example, if a 97 mV output is obtained from the DC output terminal 13 of the output unit body 2A when the test mode is entered, the value is 100 mV.
Until the voltage becomes V, the correction dial 22 is turned while watching the voltmeter connected to the DC output terminal 13 to adjust the AC amplification amount. The amplification amount determined during the test mode period is stored inside the output unit main body 2A. Further, the lock button 23 is turned on when the test mode is completed so that the correction dial 22 does not rotate due to a malfunction from the outside.

FIG. 2 shows the CT 1 for detection according to the first embodiment.
FIG. 3 is a block diagram showing main parts of A and an output unit main body 2A.

In FIG. 2, 21 is a calibration button (test switch), 25 is an oscillation circuit, 26 is an IE converter (current-voltage converter), and 27 is an E-O converter (electric signal-optical signal conversion). Vessel), 28 is ground.

In the figure, 30 is an OE converter (optical signal-electrical signal converter), 31 is an AC amplifier circuit, 2
Reference numeral 2 is a correction dial (variable resistor).

When the calibration button 21 shown in FIG. 1 is pressed, the test switch 21 shown in FIG. 2 is switched to enter the test mode when connected to the oscillation circuit 25 side and to the measurement mode when connected to the IE converter 26 side. In the test mode, the oscillation circuit 25 generates an electric signal of AC5A (corresponding to 100 mV DC), for example. The electric signal is converted into an optical signal by the EO converter 27 and then output, and then input to the output unit main body 2A via the optical fiber cable 4.

After passing through the OE converter 30, the optical signal reaches the AC amplification circuit 31, where the electric signal is oscillated by the oscillation circuit 25, for example, AC5A (DC100).
The correction dial (variable resistor) 22 is adjusted and amplified until it becomes equal to the electric signal of mV).

Therefore, in the first embodiment, since the error peculiar to the optical fiber transmission is calibrated at each site, the accuracy of measuring the high voltage current by the optical fiber type CT is improved.

That is, the calibration method is an optical fiber type CT.
A calibration signal generator (oscillation circuit 25, etc.) is built in and the level of the generated signal is adjusted by the correction dial 22 by the amount attenuated by optical fiber transmission.

According to the first embodiment, the optical fiber type C
When measuring the current of the high-voltage bus bar using T, it is impossible to perform precise measurement due to the error peculiar to the optical fiber due to the bending condition of the optical fiber cable 4 and the contamination of the connection part. A calibration process is performed every time to enable precise measurement.

Example 2. In the first embodiment, the case where the optical fiber type CT is combined with the power analyzer 3 has been described.
An optical fiber type CT is adopted as an interface for performing FT analysis. The same effect can be obtained by performing the calibration according to the calibration method of the above-described first embodiment and correcting the optical attenuation and then starting the measurement, which enables highly accurate measurement.

[0034]

As described above, the calibration method of the optical fiber type CT according to the first aspect of the present invention includes the step of generating the calibration signal in the test mode by the calibration signal generating section incorporated in the optical fiber type CT, and the output. The step of adjusting the signal sent through the optical fiber cable to be the same as the calibration signal by the correction section built in the main body of the section has the effect of improving the measurement accuracy.

As described above, the calibration method of the optical fiber type CT according to the second aspect of the present invention is such that the calibration signal generator causes the calibration button to switch between the test mode and the measurement mode and the predetermined alternating current in the test mode. An oscillation circuit that generates a current; and an EO converter that converts the predetermined AC current into an optical signal, and the correction unit has an OE converter that converts the optical signal into an AC current; Since it is composed of an AC amplification circuit that amplifies the converted AC current and a correction dial that adjusts the amplification amount of the AC amplification circuit, it is possible to easily improve the accuracy of measurement.

[Brief description of drawings]

FIG. 1 is an optical fiber type C according to a first embodiment of the present invention.
It is a top view which shows T and an output part main body.

FIG. 2 is an optical fiber type C according to the first embodiment of the present invention.
It is a block diagram which shows T and an output part main body.

FIG. 3 is an overall configuration diagram showing a situation in which measurement is performed using a conventional optical fiber type CT.

[Explanation of symbols]

1A CT for detection, 2A output unit body, 3 power analyzer, 4 optical fiber cable, 5 optical fiber connection connector (attached to CT for detection), 6 current transformer, 7 range selector switch, 8 open / close lever, 9 optical fiber connection connector (output Part main body attachment), 10 AC100V input inlet, 11 power switch, 12AC output terminal, 1
3 DC output terminal, 14 connection cable, 15-1 current input terminal (R phase), 15-2 current input terminal (T phase),
16 voltage input terminals, 17 power cord and voltage measuring cord, 18 clips, 19 PT, 20 high voltage busbars, 2
1 calibration button, 22 correction dial, 23 lock button, 24 correction dial value scale, 25 oscillation circuit,
26 IE converter, 27 EO converter, 28 ground, 30 OE converter, 31 AC amplification circuit.

Claims (2)

[Claims] 1. A step of generating a calibration signal in a test mode by a calibration signal generation section built in an optical fiber type CT, and a signal sent through an optical fiber cable by a correction section built in the output section main body as the calibration signal. A method for calibrating an optical fiber type CT, which comprises the step of adjusting so as to be the same. 2. The calibration signal generating section, a calibration button for switching between a test mode and a measurement mode, an oscillator circuit for generating a predetermined alternating current in the test mode, and converting the predetermined alternating current into an optical signal. And an O-O converter, and the correction unit converts the optical signal into an AC current.
2. The optical fiber CT according to claim 1, comprising: an -E converter, an AC amplifier circuit for amplifying the converted AC current, and a correction dial for adjusting the amplification amount of the AC amplifier circuit. Calibration method.