Download Impulse voltage and harmonic voltage distortion tests for the

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UNIVERSITY OF THE WITWATERSRAND
Private Bag 3, WITS 2050, South Africa - Telegram “Uniwits” - Telex 4-27125SA - Telephone (011) 717 7111
ELECTRIC POWER RESEARCH GROUP
Electric Power Research Group
School of Electrical and Information Engineering
Private Bag 3
WITS 2050
South Africa
Tel: (011) 717 7237
Fax: (011) 403 1929
email: [email protected]
ref: PROTEC Z.pdf
Impulse voltage and harmonic voltage distortion
tests for the ‘PROTEC Z’ unit
Prepared for: Dr. Roger Billiet
Northern Technologies
Prepared by: N. J. West and I. R. Jandrell
Date of report: April 29, 2011
Notes
• The results presented apply only to the units tested, with or without modifications as
noted in the report.
• Presentation of test results in this report does not imply approval by the University of the
product(s) tested. The results may, however, be used in promotional material as proof of
performance by the customer, but only as presented and explicitly stated in this report
1
Introduction
A ‘PROTEC Z’ unit was subjected to the following tests:
• Application of a fast voltage transient (0.5 µs rise time) with a maximum peak of 3 kV.
• Voltage harmonic distortion for 3rd, 5th, 7th, 10th and 15th harmonic
of 50 Hz, while keeping the voltage constant at 40 V.
Each phase was tested and the value of the capacitance was recorded after
each test. The capcitance was measured by means of an RLC meter.
2
Voltage impulse tests
A voltage impulse generator was used to generate the required voltage waveform. A typical open circuit voltage waveform can be seen in Figure 1. From
the figure, it can be seen that the waveform has a rise time of about 0.5 µs.
Figure 1: Typical open circuit voltage impulse waveform
Impulses of increasing peak voltage were applied to each phase of the device
and the capacitance before and after each test was measured. Impulses with
a peak voltage of 1,2 and 3 kV were applied. The results obtained can be
seen in Table 1. A typical output waveform can be seen in Figure 1.
1
Table 1: Voltage impulse tests
Phase
1
1
1
2
2
2
3
3
3
Applied
voltage [kV]
1
2
3
1
2
3
1
2
3
Output
voltage [V]
300
530
730
330
530
730
370
560
680
Capacitance
before [nF]
521
521
521
524
524
524
520
520
520
Capacitance
after [nF]
521
521
521
524
524
524
520
520
520
Figure 2: Typical output waveform for an 3 kV applied impulse
2.1
Harmonic distortion tests
In these tests, each phase of the device was subjected to 7.5% THD (Total
Harmonic Distortion) of the supplied voltage waveform for the following
harmonics: 3rd, 5th, 7th, 10th and 15th. The corresponding frequencies
can be seen in Table 2. The voltage was kept constant at 40 V throughout
2
the tests. The before and after capacitance was measured for each test. The
results of the harmonic distortion tests can be seen in Table 3. In Figures
3 and 4 typical waveforms obtained during these tests are shown. In these
figures, the voltage applied to each phase and the current drawn can be seen.
Table 2: Harmonics for f =50 Hz
Harmonic
3
5
7
9
10
15
Frequency [Hz]
150
250
350
450
500
750
Max current drawn [mA rms]
21
34
48
61
68
102
Table 3: Harmonic voltage distortion test results
Phase
Harmonic
Duration [hours]
1
1
1
1
1
1
2
2
2
2
2
2
3
3
3
3
3
3
3
5
7
9
10
15
3
5
7
9
10
15
3
5
7
9
10
15
4
1
1
0.5
0.5
0.5
4
1
1
0.5
0.5
0.5
4
1
1
0.5
0.5
0.5
3
Capacitance
before [nF]
521
521
521
521
521
521
524
524
524
524
524
524
520
520
520
520
520
520
Capacitance
after [nF]
521
521
521
521
521
521
524
524
524
524
524
524
520
520
520
520
520
520
Figure 3: 3rd harmonic: Voltage and current waveforms
Figure 4: 15th harmonic: Voltage and current waveforms
4
3
Conclusion
Fast rise time and voltage harmonic distortion tests were conducted on the
‘PROTEC Z’ unit. The voltage impulses applied had a peak of 3 kV maximum, and 3rd, 5th, 7th, 9th, 10th and 15th harmonic voltages were applied
to the device. Each one of the three phases of the unit were tested. The
tests indicated that the capacitance of each phase capacitor did not change
after each test.
N. J. West, MSc(Eng), PhD
I. R. Jandrell, PhD, PrEng
5