KR100882310B1 - Current transformer comparator system - Google Patents

Abstract

The present invention is connected to the secondary current of the standard current transformer and the current transformer to be measured and the standard current transformer and the current transformer to be measured, the secondary current of the standard current transformer and the current transformer to be measured. The present invention relates to a current transformer comparison measuring device including a current comparator to be compared and a load for a current transformer connected in series with the secondary side of the current transformer to be measured. The current transformer has a rated conversion ratio of 1: 1 and a power of 440 V / 225 A. A variable transformer for supplying power up to 440 V / 225 A, a plurality of large current generating transformers connected in parallel to generate more than 20,000 A by receiving power from the variable transformer, the standard current transformer, and the current to be measured Cylindrical busbars having a constant diameter and a predetermined length penetrating the center of the core of the transformer and the large current generating transformer, and both ends of the cylindrical busbar A plurality of phases connected in parallel with the large current generating transformer in order to improve the power factor by offsetting ground currents of the plurality of c-shaped busbars and the large current generating transformer coupled to the flange and forming bent portions on both sides. It relates to a current transformer comparison measuring device comprising a capacitor.

Current Transformer, Non Error, Phase Error, Large Current, Burden, Current Comparator, Calibration, Measurement

Description

Current transformer comparator {Current transformer comparator system}

1 is a perspective view showing a part of the configuration of the current transformer comparison measuring apparatus according to an embodiment of the present invention,

Figure 2 is a front view showing the combination of the cylindrical busbar and the c-shaped busbar and the flange according to an embodiment of the present invention,

Figure 3 is a side view showing the combination of the cylindrical busbar and the c-shaped busbar and the flange according to an embodiment of the present invention,

Figure 4 is a block diagram schematically showing the configuration of the current transformer comparison measuring apparatus according to the present invention,

5 is a graph showing the stability of the current over time at 20,000 A large current energization in the current transformer comparison measurement device according to the present invention,

6 is a graph showing a sinusoidal waveform of a large current at the time of energizing 20,000 A in a current transformer comparison measuring apparatus according to the present invention;

7 is a photograph generally showing the 20,000 A current transformer comparison measuring apparatus according to the present invention,

8 is a photograph showing a 5,000 A current transformer comparison measuring apparatus according to the present invention.

<Description of Symbols for Major Parts of Drawings>

10: variable transformer 20: large current generating transformer

21: cylindrical busbar 22: c shaped busbar

23: flange

31: Standard current transformer 32: Current transformer

31a, 32a: Primary side of standard current transformer and current transformer

31b, 32b: secondary side of standard current transformer and current transformer

40: Burden 50: Truth condenser

60: current comparator

The present invention relates to a current transformer comparison measuring apparatus, and relates to a current transformer comparison measuring apparatus capable of comparing and calibrating a current transformer of up to 20,000 A.

Currently, the Korea Research Institute of Standards and Science, a representative organization of national measurement standards, has established AC high voltage / large current standards up to 13,200 V / 3,000 A and is distributing national standards to industries. It was not able to provide measurement support to the industry because it could not establish a system.

In addition, heavy electric equipment companies need to obtain international certification of high voltage high current test equipment in order to activate the export of heavy electric equipment products and strengthen international competitiveness.

Therefore, as the global trend of transmission voltage and power capacity increase, the voltage and current range of heavy electric equipment product test is greatly increased, and at the same time, the international reliability and transparency of test report, which is the core of quality assurance, are required at stricter level. As a result, international certification of heavy electric equipment testing and traceability from national standards are indispensable.

Accordingly, the present invention has been made to solve the above problems, an object of the present invention is to build a standard current transformer which is a standard of current transformers up to 20,000 A, using a current comparator to measure 20,000 A The present invention provides a current transformer comparator that performs a performance evaluation and calibration of a current transformer of 20,000 A by comparison measurement with a current transformer.

The object of the present invention as described above is connected to the standard current transformer and the current transformer to be supplied with the same current to the primary side, and the standard current transformer and the current to be measured are connected to the secondary side of the standard current transformer and the current transformer to be measured. A current comparator comparing the secondary current of the transformer and a burden for the current transformer connected in series with the secondary side of the current transformer to be measured, with a rated conversion ratio of 1: 1 and powered by 440 V / 225 A A variable transformer that supplies 440 V / 225 A of power, a plurality of large current generating transformers connected in parallel to receive more than 20,000 A of power supplied from the variable transformer, the standard current transformer, the current transformer to be measured, and A cylindrical bus bar having a predetermined diameter and a predetermined length penetrating the center of the core of the large current generating transformer, a flange coupled to both ends of the cylindrical bus bar, and It is composed of a plurality of c-shaped bus bar coupled to the flange and bent on both sides and a plurality of phase condenser connected in parallel with the large current generating transformer to cancel the ground current of the large current generating transformer to improve the power factor It is achieved by a current transformer comparison measuring device characterized in that.

Further features and advantages of the present invention will become more apparent from the following detailed description based on the accompanying drawings. Prior to this, the terms or words used in the present specification and claims are defined in the technical spirit of the present invention on the basis of the principle that the inventor can appropriately define the concept of the term in order to explain his invention in the best way. It must be interpreted to mean meanings and concepts.

Hereinafter, with reference to the accompanying drawings showing a preferred embodiment of the present invention will be described in detail, in adding reference numerals to the components of each drawing, the same components are possible even if displayed on different drawings It should be noted that the same reference numerals are used. In describing the present invention, when it is determined that the detailed description of the related known functions or configurations may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

The present invention relates to a current transformer comparative measurement device capable of calibrating a current transformer up to 60 Hz, 20,000 A of alternating current, the standard current transformer 31 and the current transformer 32 to be supplied with the same current to the primary side. And a current comparator 60 connected to the secondary side of the standard current transformer 31 and the constant current transformer 32 to compare the secondary currents of the standard current transformer 31 and the current transformer 32 to be measured. And a load 40 for the current transformer connected in series with the secondary side of the current transformer 32 to be measured, having a rated conversion ratio of 1: 1 and being supplied with power of 440 V / 225 A and up to 440 V / 225. A variable transformer 10 for supplying power of A, a plurality of large current generating transformers 20 connected in parallel to generate power of 20,000 A or more by receiving power of the variable transformer 10, and the standard current transformer 31 ) And the current transformer (32) and the large current generating transformer (20) Cylindrical busbar 21 having a predetermined diameter and a predetermined length penetrating the center of the core, a flange 23 coupled to both ends of the cylindrical busbar 21, and bent on both sides coupled to the flange 23 A plurality of c-shaped busbars 22 having a portion and a plurality of phase condensers 50 connected in parallel with the large current generating transformer 20 to offset the ground current of the large current generating transformer 20 to improve the power factor. It is configured to include).

The output current of 20,000 A includes a variable transformer 10, a plurality of large current generating transformers 20, a cylindrical bus bar 21, a flange 23, a U-shaped bus bar 22, and a phase condenser. There is 50. When 20,000 A large current is generated, the maximum power of 440 V / 225 A is supplied to the plurality of large current generating transformers 20 using the variable transformer 10 having a rated conversion ratio of 1: 1 with an input power of 440 V / 225 A. By the busbar 21, the flange 23, and the U-shaped busbar 22, a test current of up to 20,000 A can be generated. For example, the technical description for generating a large current of 20,000 A first receives the input power of 440 V / 225 A of the laboratory distribution panel, and thus, the primary of the variable transformer 10 having a rated conversion ratio, that is, primary winding: secondary winding 1: 1. When the power is supplied to the winding, the secondary winding generates the same power of 440 V / 225 A. In addition, if the power of 440 V / 225 A is supplied to the primary winding of the large current generating transformer 20 in which the primary winding: the secondary winding is 89: 1, the voltage flowing in the secondary winding of the large current generating transformer 20 is 89. It decreases by one to 4.94 V, and the current increases by 89 times to 20,025 A current. Thus, a current of about 20,000 A flows through the cylindrical busbar 21, the flange 23, and the U-shaped busbar 22.
Therefore, since the variable transformer 10 receives an input power of 440 V / 225 A and has a rated conversion ratio of 1: 1, the variable transformer 10 may supply power of up to 440 V / 225 A (about 100 kVA) to the large current generating transformer 20. The variable transformer 10 may be configured such that the output voltage current can be finely adjusted in the range of 5% of the rating.

The large current generating transformer 20 is supplied with power of up to 440 V / 225 A through the variable transformer 10 to generate a current of up to 20,000 A. It may be configured to be connected in parallel with a large, and is connected to one side of the cylindrical bus bar 21 to be described later.
Here, two or three large current generating transformers 20 are connected in parallel because the burden for 20,000 A is less than that of the single large current generating transformer 20.

The flange 23 and the busbars 21 and 22 have a load resistance of about 300 μΩ and a current of 20,000 A or more flows through the primary side 31a and 32a of the standard current transformer 31 and the measured current transformer 32. Is produced. To this end, the cylindrical bus bar 21 may have a diameter of 12 to 18 cm, a length of 1.7 to 2.5 m, and preferably a diameter of 15 cm and a length of 2.1 m. Such a cylindrical bus bar 21 is installed penetrating through the center of the core of the standard current transformer 31, the current transformer 32 to be measured, a plurality of large current generating transformer 20.

The flange 23 is provided for easy connection between the cylindrical busbar 21 and the U-shaped busbar 22 and is formed in a circular shape to increase the contact area, and is coupled to both ends of the busbar 21. The portions in contact with the cylindrical busbar 21 and the U-shaped busbar 22 are plated with silver to reduce contact resistance.

The c-shaped busbar 22 may have a length of 2 to 2.6 m, a width of 12 to 18 cm, and a thickness of 12 to 18 mm, preferably a length of 2.3 m, a width of 15 cm, and a thickness of 15 mm. Configure. The c-shaped busbars 22 have bent portions on both sides, and the overall shape is similar to “c”, and the ends of the bent portions are radially coupled to the flanges 23 with respect to the center of the flanges 23. At this time, the portion in contact with the flange 23 was silver plated in order to reduce the contact resistance, due to which a large current of up to 30,000 A can flow.

The phase advance capacitor 50 is connected in parallel to the large current generating transformer 20 to cancel the ground current caused by the inductive reactance caused by the coil component of the large current generating transformer 20 to improve the power factor. Up to 15 fast capacitors 50 with the same capacity of 440 V, 20 kVA are connected in parallel. On the other hand, the fastening capacitor 50 is connected to the plurality of large current generating transformer 20 and the test capacitor in parallel according to the test current to adjust the capacitance value so that the power factor is close to 1 of the large current generating transformer 20 Contributes to increased efficiency.

The current comparator 60 is connected to the standard current transformer 31 and the secondary sides 31b and 32b of the current transformer to be supplied with the same large current up to 20,000 A on the primary side to compare the secondary currents of the current transformers. It is configured to measure the error and phase angle error.

The standard current transformer 31 provides a reference for measuring the error and phase angle error of the current transformer 32 under measurement, and the error of the standard current transformer 31 is 10 than the error of the current transformer 32 under measurement. The error of the standard current transformer 31 may be negligible by more than twice, and may vary depending on the range of the primary current I _p and the secondary current I _s . One example is the standard current transformer with 5000 A and 20,000 A primary currents.

The measurement results of the 5000 A standard current transformer (Type 4764, S / N: 153606) are based on the measurement of the error and phase angle error for all current ranges up to 5,000 A and the burden of 0 VA and 5 VA / PF = 1. This is within 0.001% and 0.02 min. This satisfies the manufacturer's specifications considering that the manufacturer's specifications of the standard current transformer above are ≤ ± 0.001% and the phase angle error is ≤ ± 0.05 min.

Meanwhile, another example of the standard current transformer 31 may include a 20,000 A standard current transformer (Type: NCD 20000d, S / N: 2/06/0006). The measurement result of the 20,000 A standard current transformer manufacturer satisfies the manufacturer's specifications with a tolerance of ≤ ± 0.005% and a phase angle error of ≤ ± 0.5 min.

The burden 40 for the current transformer is connected in series to the secondary side of the current transformer 32 under test, which is based on the KS standard for measuring the error and phase angle error of the current transformer.

Since the error of the current transformer 32 to be measured depends on the burden value and the power factor, accurate measurement of the burden value and the power factor is very important for the precise measurement of the non-error and phase angle error of the current transformer 32 to be measured. The burden value and power factor of the burden 40 can be measured by an automatic measurement program, and the results of the measurement are shown in Table 1.

rated burden setting value measured value burden (VA) power factor burden (VA) power factor 1 VA 1.00 1.00 1.001 1.000 1.25 VA 1.25 1.00 1.251 0.999 2.5 VA 2.50 1.00 2.496 0.999 3.75 VA 3.75 1.00 3.746 1.000 5 VA 5.00 1.00 5.003 1.000 7.5 VA 7.50 1.00 7.459 1.000 10 VA 10.0 1.00 10.02 1.000 12.5 VA 12.5 1.00 12.53 1.000 15 VA 15.0 1.00 15.06 1.000

Hereinafter, the method of measuring the error and phase angle error of the current transformer to be measured by the present invention as described above will be described.

First, before measuring the non-error and phase angle error of the current transformer 32 under measurement using the current transformer comparison measuring device according to the present invention, the output stability of 20,000 A large current is investigated using the busbars 21 and 22. It was. The output of the current 20,000 A measures the stability of the current generating source of 20,000 A by attaching a resistance of 0.4 Ω to the secondary side of the current transformer in which the ratio of primary current and secondary current is 20,000 A: 5 A. It was. 5 is a result of measuring a large current of 20,000 A while flowing for 10 minutes. The reason why the output current decreases gradually with time is that heat is generated in the busbars 21 and 22 and the resistance of the busbars 21 and 22 is increased. The relative standard deviation of the stability of the output current was very good at 0.12%. Considering that the measurement time of the current transformer 32 to be measured is typically about 2 to 3 minutes, it can be seen that the output stability is hardly affected by the measurement.

FIG. 6 measured the current waveform of the secondary side of the current transformer of 20,000 A: 5 A when a current of 20,000 A flowed using a digital oscilloscope. It can be seen that there is no distortion of the large current sinusoid when the 20,000 A current is energized.

Referring to the operation relationship of the current transformer comparison measuring device according to the present invention under the above conditions are as follows.

The current transformer comparison and measurement device thus constructed can calibrate the current transformer 32 under measurement of the primary current I _p = 0.05 A to 20,000 A. The current transformer comparison measuring device uses two standard current transformers 31 according to the current measurement range of the current transformer 32 to be measured. When the primary side current I _p = 5 000 A or more of the current transformer 32 to be measured, a cylindrical busbar 21 having a diameter of 15 cm is used by using a standard current transformer having a primary current I _p = 5,000 A to 20,000 A. To measure the error and phase angle error of the current transformer 32 under measurement. 7 is a photograph generally showing the 20,000 A current transformer comparison measuring apparatus according to the present invention.

On the other hand, when the primary side current I _p of the current transformer 32 to be measured is less than 5,000 A, and the primary side is a through-type, a 5,000 A standard current transformer and a cylindrical busbar 21 having a diameter of 7 cm are used. The measurement error and phase error of the current transformer 32 is measured. 8 is a photograph showing a 5,000 A current transformer comparison measuring apparatus according to the present invention.

In the above two cases, the measurement method uses the busbars 21 and 22 to supply the same current in series to the primary side of the standard current transformer 31 and the current transformer 32 to be measured, and 2 of the two current transformers. By comparing the current on the side with the current comparator 60, the error and phase error of the current transformer 32 to be measured are measured. This method measures the error and phase angle error of the current transformer 32 under measurement based on the standard current transformer 31 which can ignore the error and phase angle errors compared to the current transformer 32 under measurement. As a result of the test operation, it was confirmed that the test of the current transformer to the primary current of 20,000 A operates normally. In addition, the current transformer comparator was able to confirm that the variation of the error and the phase error were very stable within 0.0002% and 0.005 min, respectively.

Hereinafter, the results of evaluating the performance of the current transformer comparison measuring apparatus according to the present invention in comparison with international comparison measurement will be disclosed.

In order to evaluate the performance of the current transformer comparator, an international comparison with the Australian National Standards Institute (NMIA) was performed using a 5,000 A current transformer (type P-5000, S / N: 0490961) as a mobile standard current transformer. Measurements in the KRISS were made using a 5,000 A standard current transformer (type 4764, S / N: 153606) and a copper busbar 7 cm in diameter. Since the non-error and phase angle error of the current transformer 32 under measurement are measured based on the standard current transformer 31, the relationship between the non-error measurement value of the current transformer 32 under measurement and the actual error is as follows.

= 실제 피측정 전류변성기의 비오차, here

= Error of the current transformer to be measured,

= 표준 전류변성기의 비오차,

= Error of the standard current transformer,

= 전류변성기 비교기에서 측정되는 비오차.

= Non-error measured in the current transformer comparator.

In order to calculate the error of the actual current transformer 32 under Equation 1, the error value of the standard current transformer 31 is added to the value measured by the current comparator 60 to be corrected. This correction value was taken from the measured value of the 5,000 A standard current transformer manufacturer, and the error of the actual current transformer 32 to be measured was obtained. The results of non-error measurements at KRISS are shown in the third column of Table 2. Here, the measurement conditions are 5%, 20% and 100% of the secondary side currents in the range of 0 VA, 60 Hz, and the primary side currents of the current transformer of 10 A to 3,000 A.

On the other hand, the results of non-error measurements in Australia NMIA under the same test conditions using the same mobile current transformer measured by KRISS are shown in the fourth column of Table 2. The discrepancies in both organs are shown in the last column of Table 2, which shows a fairly good agreement with a maximum of 0.002%.

Rated primary current / Rated secondary current Secondary current (%) Ratio error (%) Difference (KRISS-NMIA) KRISS NMIA 10 A / 5 A 5 20 100 +0.000 -0.001 -0.001 +0.000 +0.000 +0.000 +0.000 -0.001 -0.001 15 A / 5 A 5 20 100 +0.000 -0.001 -0.001 +0.000 +0.000 +0.000 +0.000 -0.001 -0.001 20 A / 5 A 5 20 100 +0.000 -0.001 -0.001 +0.000 +0.000 +0.000 +0.000 -0.001 -0.001 25 A / 5 A 5 20 100 +0.000 -0.001 -0.001 +0.000 +0.000 +0.000 +0.000 -0.001 -0.001 50 A / 5 A 5 20 100 +0.000 -0.001 -0.001 +0.001 +0.000 +0.000 -0.001 -0.001 -0.001 75 A / 5 A 5 20 100 +0.000 -0.001 -0.002 +0.001 +0.000 +0.000 -0.001 -0.001 -0.002 100 A / 5 A 5 20 100 -0.001 -0.001 -0.002 +0.000 +0.000 -0.001 -0.001 -0.001 -0.001 300 A / 5 A 5 20 100 +0.000 -0.001 -0.002 +0.000 +0.000 +0.000 +0.000 -0.001 -0.002 600 A / 5 A 5 20 100 -0.001 -0.001 -0.001 +0.001 +0.000 +0.000 -0.002 -0.001 -0.001 750 A / 5 A 5 20 100 +0.000 -0.001 -0.001 +0.000 +0.000 -0.001 +0.000 -0.001 +0.000 1000 A / 5 A 5 20 100 +0.000 -0.001 -0.001 +0.000 -0.001 -0.001 +0.000 +0.000 +0.000 1500 A / 5 A 5 20 100 +0.001 +0.000 -0.001 +0.000 +0.000 -0.001 +0.001 +0.000 +0.000 2000 A / 5 A 5 20 100 +0.001 +0.000 +0.000 -0.001 -0.001 -0.001 +0.002 +0.001 +0.001 3000 A / 5 A 5 20 100 +0.000 +0.000 -0.001 -0.002 -0.002 -0.002 +0.002 +0.002 +0.001

Similarly to Equation 1, the relationship between the phase angle error measurement value of the current transformer 32 under test and the phase angle error of the current transformer 32 under measurement is as follows.

= 실제 피측정 전류변성기의 위상각 오차here

= Phase angle error of the current transformer

= 표준 전류변성기의 위상각 오차,

= Phase angle error of standard current transformer,

= 전류변성기 비교기에서 측정되는 위상각 오차.

= Phase angle error measured by the current transformer comparator.

In order to calculate the phase angle error of the current transformer 32 to be measured in Equation 2, the phase angle error value of the standard current transformer 31 is added to the value measured by the current comparator 60 to be corrected. This correction value was taken from the measured value of the 5,000 A standard current transformer manufacturer, and the phase angle error of the actual current transformer 32 to be measured was obtained. Phase angle error measurement results in KRISS are shown in the third column of Table 3. Here, the measurement conditions are the same as in the previous measurement of the error.

The results of phase angle error measurements in Australia NMIA for the same test conditions using the same mobile current transformer 31 measured by KRISS are shown in the fourth column of Table 3. The discrepancies in both organs are shown in the last column of Table 3, with a fairly good agreement of up to 0.09 min.

Rated primary current / Rated secondary current Secondary current (%) Phase displacement (min) Difference (KRISS-NMIA) KRISS NMIA 10 A / 5 A 5 20 100 +0.09 +0.04 -0.04 +0.00 +0.00 -0.07 +0.09 +0.04 +0.03 15 A / 5 A 5 20 100 +0.10 +0.04 -0.05 +0.03 +0.00 -0.07 +0.07 +0.04 +0.02 20 A / 5 A 5 20 100 +0.09 +0.04 -0.05 +0.00 -0.03 -0.07 +0.09 +0.07 +0.02 25 A / 5 A 5 20 100 +0.09 +0.03 -0.05 +0.00 +0.00 -0.07 +0.09 +0.03 +0.02 50 A / 5 A 5 20 100 +0.08 +0.02 -0.07 +0.03 +0.00 -0.07 +0.05 +0.02 +0.00 75 A / 5 A 5 20 100 +0.07 +0.01 -0.08 +0.03 +0.00 -0.07 +0.04 +0.01 -0.01 100 A / 5 A 5 20 100 +0.07 +0.01 -0.09 +0.07 +0.00 -0.03 +0.00 +0.01 -0.06 300 A / 5 A 5 20 100 +0.09 +0.02 -0.07 +0.03 +0.00 -0.03 +0.06 +0.02 -0.04 600 A / 5 A 5 20 100 +0.08 +0.01 -0.08 +0.07 +0.00 -0.03 +0.01 +0.01 -0.05 750 A / 5 A 5 20 100 +0.06 +0.01 -0.07 +0.07 +0.03 -0.03 -0.01 -0.02 -0.04 1000 A / 5 A 5 20 100 +0.03 -0.01 -0.07 +0.07 +0.00 -0.03 -0.04 -0.01 -0.04 1500 A / 5 A 5 20 100 +0.09 +0.03 -0.03 +0.07 +0.03 -0.03 +0.02 +0.00 +0.00 2000 A / 5 A 5 20 100 +0.06 +0.02 -0.04 +0.10 +0.03 -0.03 -0.04 -0.01 -0.01 3000 A / 5 A 5 20 100 +0.04 +0.00 -0.05 +0.07 +0.03 -0.03 -0.03 -0.03 -0.02

On the other hand, in order to evaluate the performance of the current transformer comparator, the German national standard uses a 20 kA current transformer (NCD 20000d, S / N: 2/06/0006) as a mobile current transformer in a similar manner to the previous international comparison with Australia. International comparisons were conducted indirectly with the PTB.

Measurements in the KRISS were measured using a busbar 21 having a diameter of 15 cm to generate a current of 20,000 A. As the standard current transformer 31, a 20,000 A current transformer (NCD 20000d, S / N: 2/06/0007) was used. The non-error measurement value of the actual current transformer 32 under measurement in KRISS was obtained in the same manner as in <Equation 1>. The measurement conditions at both engines are 10%, 20%, 50% and 100% of secondary side currents in the range of 5 VA, PF = 1, 60 Hz and primary side currents of 5,000 A to 20,000 A of current transformers. Non-error measurements at both organs are shown in Table 4, and the last column of Table 4 shows the difference in measurements at both organs. The discrepancies in both organs are up to 0.004%, which shows a fairly good agreement.

Rated primary current / Rated secondary current Secondary current (%) Ratio error (%) Difference (KRISS-PTB) KRISS PTB 5000 A / 5 A 10 20 50 100 +0.004 +0.004 +0.004 +0.003 +0.007 +0.007 +0.007 +0.007 -0.003 -0.003 -0.003 -0.004 10000 A / 5 A 10 20 50 100 +0.008 +0.008 +0.007 +0.007 +0.010 +0.010 +0.010 +0.010 -0.002 -0.002 -0.003 -0.003 15000 A / 5 A 10 20 50 100 +0.006 +0.006 +0.005 +0.005 +0.008 +0.008 +0.007 +0.007 -0.002 -0.002 -0.002 -0.002 20000 A / 5 A 10 20 50 100 +0.004 +0.003 +0.003 +0.003 +0.007 +0.007 +0.006 +0.006 -0.003 -0.004 -0.003 -0.003

As in Table 4, Table 5 shows the measurement results of the phase angle errors measured by both engines. The inconsistency in both organs is up to 0.1 min, showing a fairly good agreement.

Rated primary current / Rated secondary current Secondary current (%) Phase angle error (min) Difference (KRISS-PTB) KRISS PTB 5000 A / 5 A 10 20 50 100 -0.5 -0.6 -0.6 -0.7 -0.5 -0.6 -0.6 -0.6 +0.0 +0.0 +0.0 -0.1 10000 A / 5 A 10 20 50 100 -0.1 -0.1 -0.3 -0.3 -0.2 -0.2 -0.2 -0.2 +0.1 +0.1 -0.1 -0.1 15000 A / 5 A 10 20 50 100 -0.1 -0.1 -0.2 -0.2 -0.2 -0.2 -0.2 -0.2 +0.1 +0.1 +0.0 +0.0 20000 A / 5 A 10 20 50 100 -0.2 -0.2 -0.2 -0.2 -0.1 -0.1 -0.1 -0.2 -0.1 -0.1 -0.1 +0.0

As described above, according to the present invention, as the voltage and current range of heavy electric product test are greatly increased with increasing transmission voltage and power capacity, the high current / high voltage heavy electric machine can be evaluated and calibrated. And, there is an effect that can improve the product defect rate of heavy electric machines.

Although the present invention has been described in connection with a preferred embodiment, those of ordinary skill in the art will be able to easily make various changes and modifications without departing from the essential characteristics of the present invention. Therefore, the disclosed embodiments should be considered in descriptive sense only and not for purposes of limitation, and the true scope of the present invention is shown in the claims rather than the foregoing description, and all differences within the equivalent scope are included in the present invention. Should be interpreted as.

Claims (9)

The standard current transformer 31 and the current transformer 32 to be supplied with the same current to the primary sides 31a and 32a, and the secondary side 31b of the standard current transformer 31 and the current transformer 32 to be measured 32. 32b), a current comparator 60 for comparing the currents of the standard current transformer 31 and the secondary side 31b, 32b of the current transformer 32 to be measured, and the secondary side of the current transformer 32 to be measured. In the current transformer comparison measuring device comprising a load 40 for the current transformer connected in series with (32b), A variable transformer having a rated conversion ratio of 1: 1 and receiving a power of 440 V / 225 A and supplying a maximum of 440 V / 225 A; A plurality of large current generating transformers 20 connected in parallel to receive power of the variable transformer 10 to generate 20,000 A or more; A cylindrical busbar 21 having a predetermined diameter and a predetermined length penetrating the center of the core of the standard current transformer 31, the current transformer 32 to be measured, and the large current generating transformer 20; A flange 23 coupled to both ends of the cylindrical bus bar 21, and a plurality of c-shaped bus bars 22 coupled to the flange 23 and having bent portions on both sides; And A plurality of phase condenser 50 connected in parallel with the large current generating transformer 20 to cancel the ground current of the large current generating transformer 20 to improve the power factor; Current transformer comparison measuring device, characterized in that configured to include. The method of claim 1, The resistance of the flange (23) and the busbars (21, 22) is a current transformer comparison measuring device, characterized in that made using less than 300 μΩ. The method of claim 1, The surface of the flange 23 is plated with silver to improve the conductivity of the current transformer, characterized in that to improve the conductivity of the cylindrical bus bar (21) and the c-shaped bus bar (22). The method of claim 1, The phase change capacitor 50 is a current transformer comparative measurement, characterized in that to use the capacity of 440 V, 20 kVA to improve the efficiency of the large current generating transformer 20 by adjusting the capacitance value so that the power factor is close to 1 Device. The method of claim 1, Fine control of the variable transformer 10 is a current transformer comparison measuring device, characterized in that the output voltage current is within 5% of the rating. The method of claim 1, The plurality of large current generating transformer 20 is a current transformer comparison measuring device, characterized in that using the same capacity and specifications to generate a large current of 20,000 A. The method of claim 1, The c-shaped bus bar 22 is provided with a plurality of current transformer comparison measuring device, characterized in that coupled to the radially symmetrical with respect to the center of the flange (23). The method of claim 1, Diameter of the cylindrical bus bar 21 is 12 ~ 18 cm, length is 1.7 ~ 2.5 m current transformer comparison measuring device characterized in that. The method of claim 1, The c-shaped bus bar 22 has a length of 2 to 2.6 m, a width of 12 to 18 cm, the thickness of the current transformer comparison measuring device, characterized in that 12 to 18 mm.

Images