HCL 2010 Partial Discharge Measuring and Analysis System

Mode: HCL 2010 Digital Partial Discharge Tester

Applied Standards :
IEC60270     《Partial discharge measurement》
IEC60885-3  《Test methods for partial discharge measurements on lengths of extruded power cables》
DL417           《Partial discharge testing guide for power equipment》
GB/T16927  《High-voltage test technique》
IEC60060-1&2; IEC-885; IEEE Std.4

Application Scope:
Kinds of voltage grade and capacity transformer, power generator, instrument transformer, bushing, GIS, electric cable, switch, HV equipment. 

 
Features: 
The capability of one partial discharge analyzer with single channel digital partial discharge measurement and adopting synchronous sampling, processing and displaying, equals to 6 single channel (selectable)partial discharge tester.
Measure, statistic and analyze the count of repeat partial discharge.
Choose the inner and external synchronization arbitrarily, and have the function of zero indication and phase identification.
Choose the ellipse, line, sine display form freely.
Analyze single discharge pulse waveform, and identify the type of the discharge.
Save the experiment data and waveform on schedule automatically.
Save the experiment data and waveform any time manually.
Redisplay and analyze the history experiment data.
Gain range: channels adjust the scale respectively, and the waveform display can be adjusted smoothly any time without influencing the result .
Capture the special and random waveform at single time, and make detail analysis.
With function of correlation filtering, it can eliminate the random interference asynchronous with the power.
The partial discharge intelligence identify system identifies the interference and partial discharge signals automatically in certain circumstance, and eliminates the interference.
When testing the partial discharge, it can also monitor the experiment voltage .
Can display the discharge voltage and the quantity.
Display the discharge current, discharge times and discharge power
Can update the partial discharge locating and on-line monitoring function according the users' needs.
Locating to PD (Selectable)
The Result Analyzing
Analyze the quantity, discharge time, time-domain and frequency–domain.
Measure and observe the single partial discharge pulse, then determine the type of the discharge. 2-dimension, 3-dimension and multiple parameter analysis partial discharge diagram display.
Form and Print the Report Automatically
Save, print partial discharge diagram and data arbitrary, and form the reports automatically.
save, edit the partial discharge diagram and data arbitrary.
Calibrator: will be equipped according to different test object.
With different range: 5pC, 10pC, 50pC, 100pC, 500pC1000pC, 2000pC, 5000pC  e.g.
Input impedance: will be equipped according to different test object.

Typical Discharge Model and Identification of Interference: 

1. Characteristics of discharging waveforms of typical internal bubbles
   A. Discharge is in the two ellipse quadrants of the test voltage from 0 to peak.
   B. The discharge often occurs near the peak at the initial voltage (Ui). But if the test voltage exceeds Ui, the discharge extends to the zero phase.
   C. Both the amplitude and number of discharge at two opposite half-cycles are roughly the same (Max difference 3:1).
   D. Discharge waveforms can be identified.
   E. The quantity of discharge bears little relation to test voltage but the repetition rate (n) increases as the test voltage rises.
   F. The initial voltage of partial discharge (Ui) is roughly equal to the extinction voltage (Ue).
   G. There is little relation between discharge quantity (q) and time.
   H. If the quantity of discharge increases with the rising of test voltage, and discharge waveforms become blurred, then there may be many air bubbles in the medium or the discharge happens at the surface of media. In addition to the above condition, the discharge amplitude increases (up to 100 times or more), bubbles in the insulating liquids are most likely to discharge. The typical example is oil-immersed capacitor.

   
   

2. Characteristics of discharge waveforms of bubbles between the metal and medium
A. There are many small discharges at the positive half-cycle. There are few bigger discharges at the negative half-cycle. The difference of amplitude is up to 10:1.
B. Typical example: discharge of XLPE cable with poor attachment between conductor and insulation. There is little relation between partial discharge value and test voltage (Fig.2). 

C. If the amplitude of discharge increases with rising of test voltage, and discharge waveforms become blurred, then there may be many air bubbles in different sizes or the discharge happens between exposed metal and medium surface (Fig.3).

Phenomenon of Interference (or Abnormal Discharge)

1.Characteristics of discharging waveforms of floating potential objects
The amplitude appears in the two quadrants of positive and negative half-cycles before voltage peak. The number of pulses and positions are the same, appearing in pairs. The discharge is movable but the gap between each other keeps the same. With the rising of voltage, the number of pulses increases. The gap decreases while the amplitude does not change. Sometimes it will disappear when the voltage rises to a given value, but it will also appear when voltage decreases to this given value.
Reason: Discharge generating in the gaps between metals. (Fig.4)

2.Characteristics of corona discharge waveforms at the external tip

The initial discharge merely appears at a half-cycle of test voltage and distributes symmetrically at both sides of peak. When the test voltage rises, discharge pulses will increase rapidly. But the amplitude is constant, and extends to two sides.
Reason: High-voltage tip in the air or margin discharges. If the discharge happens at the negative half-cycle, it means that the tip is at high-voltage. If the discharge appears at he positive half-cycle, the tip will be at the ground potential.(Fig.5)

3. Characteristics of corona discharge waveforms at the liquid medium tip

The discharge happens at two half-cycles and distributes symmetrically at both sides of peak. Each group of discharge is the same gap. However, a group of discharge with bigger amplitude appears firstly. Its amplitude increases but not equal as the test voltage rises; another group of discharge with small amplitude has the same amplitude and does not vary according to the test voltage.

Reason: The tip in the insulating liquid or margin discharges. For example, if a group of bigger discharge appears at the positive half-cycle, then the tip is at high voltage; if it appears at the negative half-cycle, then the tip is at the ground potential.(Fig.6)

4.Interference of poor contact
Waveform features: distribute symmetrically at both sides of test voltage zero point; the amplitude is roughly the same but reduces to zero around the voltage peak. The waveform is blurred and appears at low voltage. When the test voltage rises, the amplitude of pulse will increase slowly. Sometimes, it will disappear completely at a special voltage.(Fig.7)

5.Interference from SCR element
Waveform features: fixed location. Every component generates an individual signal. The amplitude of signal increases as the electromagnetic coupling affect intensifies. When regulating the test voltage, the pulse will have high-frequency waveform extension,thus increasing the placeholder. (Fig.8)
Reason: The SCR element is running nearby. 

6.Interference from relay, contactor and glow tube
The waveforms are irregularly distributed. There is no relation with test voltage. The interference generates when thermal relay, contactor, spark device and recorder work.(Fig.9)

7. Interference from fluorescence light
The waveforms look like fences. The amplitude is roughly the same with two groups of pulses at the positive and negative waveform. The reason is that the fluorescence light is on.(Fig.10)

8. Wireless interference
AM/FM high frequency sine waveform. There is no relation with test voltage. Sources are mobile phone, microphone and carrier communication etc.(Fig.11)

9. Interference of motor
The discharge waveforms distribute uniformly on the ellipse baseline. Possible causes are motor, fan and hair dryer etc.(Fig.12)

10. Interference from middle/high frequency industrial equipment

The waveforms happens continuously and only appears on the half-cycle of power waveform. Equipment such as Induced heating instrument and ultrasonic generator.(Fig.13)

11.Interference of magnetic saturation harmonic wave
Harmonic oscillation at low frequency; appears at two half-cycles; the amplitude increases as the test voltage goes up. It disappears in case of no voltage applying. The interference is from all iron instruments in the test system (test transformer, reactor and isolating transformer).(Fig.14)

12. Interference of electrode moving in the direction of electric field
The amplitude is the same, but the direction of pulse is contrary. Two pulses are near at the peak of initial voltage. When the voltage rises, pulses will detach gradually and new pulses maybe generate .(Fig.15)

13. Current leakage and branch discharge
The discharge signals are not in accordance with the general typical image. Waveforms are irregular and unidentified. 

About the feeding voltage and frequency:

When order PD tester, please kind confirm the input voltage and frequency with our sales manager.
Considering different country voltage is different, the PD tester need customized on it. And what we need is single phase voltage.