JP4767048B2 - Ratio ratio and polarity judgment method of current transformer, and apparatus therefor - Google Patents

Description

The present invention relates to a method for determining a ratio ratio and polarity of a current transformer required for testing a current transformer (CT) circuit of a control panel or a distribution board, and an apparatus therefor.

  Conventionally, in the test of the current transformer circuit of the control panel and the switchboard, the ratio ratio and the polarity test are respectively performed to determine whether the current transformer circuit is acceptable or not. That is, for example, since there is no instrument that directly measures the current 500A of the high voltage circuit, it is insulated from the high voltage circuit using a current transformer, and the large current 500A is converted into a 1/100 5A easy-to-handle current. Whether the ratio ratio of “1/100” is obtained is measured as a ratio ratio test. In addition, because the internal circuit is complicated in the control panel and switchboard, the wiring is complicated and the current transformer is tested to see if it is connected correctly, that is, by conducting a polarity test. It must be checked whether the wiring connection of the instrument is correct. This polarity test is a test of whether the connection of the current transformer is correct by passing a current through a combination of batteries such as dry batteries with a clear polarity. The test results are obtained by looking at the direction of deflection of the connected ammeter or voltmeter.

  As described above, the ratio ratio test and the polarity test must be performed separately in the control panel and switchboard current transformer circuit tests. It is implemented separately and is very time consuming and labor intensive. That is, in the ratio ratio test, current must actually flow through the circuit, and in the polarity test of the connection of the current transformer, it is checked whether a correct connection is made by connecting a battery. Is what you do. Especially for control panels and switchboards, there is a possibility that an abnormality may occur before shipping even if there is no abnormality at the time of assembly at the factory. It is an indispensable requirement to perform the ratio ratio test and polarity test described above. is there.

Invention of claim 1, the current side output of the voltage / current converter connected to the voltage regulator, through the meter for the primary side and measuring the current, the current flowing in the primary bus of a plurality of phases more Connecting to the primary bus of any one of the current transformers that convert to a small current and output to the secondary side, and the phase of the voltage output from the voltage side output of the voltage / current converter to the current input side The current input side of the phase meter shown in comparison with the phase of the current taken in from is shown in association with the buses on the primary side of the plurality of phases of the current transformer via an ammeter switching switch (AS). A secondary side corresponding to a primary bus of the current transformer to which the current side output of the voltage / current converter is connected. a step of switching to, by operating the voltage regulator, the voltage / current Wherein the current of the current side output of the exchanger on the basis of the value indicated by the meter for the primary side and a step of setting the predetermined value, setting the current of the current side output of the voltage / current converter to the predetermined value in state, the read current flowing through the secondary side for meter for measuring the secondary current of the transformer were measured ratio ratio of the current transformer, at the same time, of the current transformer by the phase meter It is the ratio ratio and polarity determination method of a current transformer which enabled it to confirm polarity.

According to a second aspect of the present invention, there is provided a voltage regulator for adjusting a voltage applied from a power source to a predetermined voltage , a voltage / current converter to which a voltage from the voltage regulator is applied, and a plurality of primary buses and a meter for the primary side to measure the connected current of the current side output of the voltage / current converter to the primary side of the current transformer for outputting the secondary side to convert the current into a smaller current through the variable An ammeter switching switch (AS) connected to each secondary side shown in correspondence with the buses on the primary side of the plurality of phases of the current transformer, and the current transformer via the ammeter switching switch (AS) A secondary-side meter connected to the secondary side of the detector and measuring the current flowing to the secondary side, the phase of the voltage output from the voltage-side output of the voltage / current converter, and the ammeter switching switch (AS) Compared with the phase of the current on the secondary side of the current transformer taken in via A phase meter, a ratio ratio and polarity determination device current transformer become more.

  In the present invention, in the state where the voltage / current converter and the phase meter are connected to the current transformer, the ratio ratio of the test current to the current transformer is measured and the polarity of the connection of the current transformer is confirmed. It is possible to measure one requirement at a time, so that it is only necessary to connect related instruments required for the test, and the ratio of the test current to the current transformer can be measured. Since the two requirements of confirming the polarity of the connection of the current transformer can be known at a time, the time and labor can be easily reduced.

  Embodiments of the present invention will be described with reference to the drawings. First, a voltage regulator 3 is connected to an AC 100V power source 1 via a circuit breaker 2 labeled MCCB. A voltage / current converter 4 is connected to the voltage regulator 3. A test object 7 including two current transformers 5 and 6 is connected to the current side output of the voltage / current converter 4. That is, the current side output of the voltage / current converter 4 is connected to the red phase bus K side and L side of the DUT 7. A primary side meter 9 for measuring a current flowing through the connection line 8 is connected between the current side output of the voltage / current converter 4 and the DUT 7. A phase meter 10 is connected to the voltage side output of the voltage / current converter 4. The phase meter 10 is connected to the secondary side of the DUT 7 via a secondary meter 11 and a changeover switch 12. The secondary connection point is a portion indicated by red, white, and blue.

  The change-over switch 12 has the configuration shown in FIG. 2, and the phase meter 10 and the secondary meter 11 are connected to connection points 2, 4, 6, 8. 5 is connected to red, connection points 3 and 7 are connected to blue, and connection point 6 of the secondary side meter 11 is connected to white.

  Next, the device under test 7 is composed of two current transformers 5 and 6 each having a coil sensitive to the current flowing through the red phase bus, white phase bus, and blue phase bus that serve as the lines. , 1 and 2 are connected to the red, blue and white connection points of the change-over switch 12, respectively.

  In such a configuration, first, prior to the test, the voltage regulator 3, the voltage / current converter 4, the primary meter 9, the phase meter 10, and the secondary meter 11 connected as shown in FIG. The changeover switch 12 is connected to the DUT 7. Then, with the circuit breaker 2 turned on, the voltage regulator 3 is operated to apply 200 V / 500 A to the voltage / current converter 4. In this voltage / current converter 4, it is normal for current to flow as a current side output with a ratio ratio of 500 V / 200 A, but the current side output of the voltage / current converter 4 is measured by the primary side meter 9. The voltage regulator 3 is adjusted so that the value of current flowing through it becomes 200A. At this time, the current side output of the voltage / current converter 4 is connected to the red phase bus K side and L side of the DUT 7, and the three lead wires of the changeover switch 12 are connected to the DUT 7. It is connected to red, white and blue on the power supply side of the current transformer terminal.

  In this state, the voltage regulator 3 is operated to increase the voltage so that the current flowing through the primary side meter 9 is adjusted to 200 A predetermined for the test. In this state, the secondary side meter 11 indicates the current. Confirm that the current value is 2A. Thereby, it is confirmed that the operation is performed at a predetermined normal ratio ratio. At the same time, the phase meter 10 confirms that the phase is delayed by 30 °. In the case of three phases, it is normal that the phase is 30 ° behind. Then, when the changeover switch 12 is switched to the white phase and the blue phase, respectively, it is confirmed that the display on the secondary side meter 11 becomes “0” and the phase indicated by the phase meter 10 also deviates significantly from 30 °. .

  Moreover, the current / phase can be confirmed in the same manner by connecting the white phase connection of the lead wire to the ground. This ground connection may be any part of the device, and such a measurement confirms the normal state in which the white phase is grounded. Incidentally, when the white phase does not fall to the ground, the current transformer circuit does not operate.

  In this way, the measurement of the current ratio and the confirmation of the polarity of the connection of the current transformer can be confirmed at the same time by one connection for the test, and the reduction of time and labor is remarkable.

It is a circuit diagram which shows the embodiment of this invention. It is a circuit diagram which shows the structure of a changeover switch.

Explanation of symbols

3 Voltage regulator 4 Voltage / current converter 7 DUT 9 Primary side meter 10 Phase meter 11 Secondary side meter

Claims (2)

The current-side output of the voltage / current converter connected to the voltage regulator is converted into a smaller current through the primary-side bus of multiple phases through the primary-side meter that measures the current. Connecting to the primary bus of any one of the current transformers that output to the side ,
The current input side of the phase meter shown by comparing the phase of the voltage output from the voltage side output of the voltage / current converter with the phase of the current taken from the current input side, an ammeter switching switch (AS) And connecting to the secondary side shown in association with the bus on the primary side of the plurality of phases of the current transformer,
Switching the ammeter switching switch (AS) to a secondary side corresponding to a primary bus of the current transformer connected to a current side output of the voltage / current converter;
And setting to a predetermined value the operating the voltage regulator, based on the voltage / current converter of the current-side output of the current to the value indicated by the primary side for the meter,
With
In a state where the current of the current side output of the voltage / current converter is set to the predetermined value, the current transformer reads the current flowing through the secondary side for meter for measuring the secondary current of the transformer the ratio ratio was measured, at the same time, said to be able to check the polarity of the current transformer, the ratio ratio and polarity determination method of current transformer, characterized in that by the phase meter. A voltage regulator for adjusting the voltage applied from the power source to a predetermined voltage;
A voltage / current converter to which the voltage from the voltage regulator is applied;
A primary side that measures the current of the current side output of the voltage / current converter connected to the primary side of the current transformer that converts the current flowing through the primary side buses of the plurality of phases into a smaller current and outputs it to the secondary side Meter for
An ammeter switching switch (AS) connected to each secondary side shown in correspondence with the buses on the primary side of the plurality of phases of the current transformer;
A secondary side meter connected to the secondary side of the current transformer via an ammeter switching switch (AS) and measuring a current flowing to the secondary side;
Compared to the phase of the voltage output from the voltage side output of the voltage / current converter and the phase of the current on the secondary side of the current transformer taken in via the ammeter switching switch (AS) A phase meter ,
A ratio ratio and polarity determination device for a current transformer, characterized by comprising:

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