High Voltage Equipment

Basics of High-Voltage Test Techniques

HV Test Systems and Their Components

HV generators. a For AC test voltage 1,000 kV at Cottbus Technincal University. b For DC test voltage 1,500 kV Cologne. c For LI/SI test 2,400 kV at Dresden Technical University

Measuring systems a Voltage measuring system with digital recolrder including impluse generator. b Compact capacitance/loss factor measuring system with integrated AC voltage source(Courtesy of Double-Lemke). c Partial discharge measuring system including AC voltage test circuit(Courtesy of Double-Lemke)

HV Measurement and Estimation of the Measuring Uncertainty

This section is realted to voltage measurement and describes HV measuring systems, their calibration and the estimation of their uncertainties of measurements. Precise measurement of high test Voltage is considered to be a difficult tast for many years(Jouaire and Sabot et al. 1978; "Les Renardieres Group" 1974). This situation is also reflected by the olderneditions of the relevant standard IEC 60060-2. For good practice in HV test fields, this Sect. 2.3 on HV measurement and uncertainty estimation is closely related to the newest edition of the standard IEC 60060-2:2010.

The terms "uncertainty","error" and "tolerance" are often mixed up. therefore, the following clarification seems needed: The uncertainty is a parameter which ia associated with the result of a measurement. It characterizes the dispersion of the measured quantity minus a reference value for this quantity and the tolerance is the permitted difference between the measured and the specified value. Tolerance is the permitted difference between the measured and the specified value. Tolerance play a role for standard HV test procedures(sects. 3.6,6.5 and 7.6). Uncertainties are import for the decision, whether a measuring system is applicable or not for acceptance testing.

Current Transformers

Calibration (accuracy test):
(using "primary injection" method)
  • at primary currents up to 5000 A at 50 Hz
  • at rated secondary currents of 1 A or 5 A.

to Standards:

  • AS 60044.1
  • AS 1675
  • IEC 61869-2
  • includes polarity check

Least Uncertainties:
Current Error: ±0.025%
Phase Displacement: ±0.05 crad or ±1.7 min

Voltage Transformers

Calibration (accuracy test):
(using "primary injection" method)
  • at primary voltages up to 100 kV at 50 Hz
  • at rated secondary voltages of 63.5 V or 110 V..

to Standards:

  • AS 60044.2
  • AS 1243
  • IEC 61869-3
  • includes polarity check

Least Uncertainties:
Voltage Error: ±0.03%
Phase Displacement: ±0.06 crad or ±2 min

High Voltage Voltmeters/Dividers

Calibration:
  • DC: (+ve or -ve) up to 90 kV (if HV DC test supply provided)
  • DC: (+ve or -ve) up to 50 kV (if HV DC tets supply not provided)
  • AC rms: up to 100 kV
  • AC peak (+ve or -ve) up to 140 kV
  • AC peak/√2 (+ve or -ve) up to 100 kV
Least Uncertainties:
  • DC: ±2% of reading or ratio
  • ACrms: ±4%
  • ACpeak: ±4%
  • ACpeak/√2: ±4%

X-ray Dividers (medical, scientific)

As above for HV Voltmeters/Dividers

Insulation Resistance Testers

Calibration:
  • at voltages up 5 kV d.c.
  • from 1 MΩ to 100 GΩ
Least Uncertainties:
  • DIgital meters: ±3% of reading
  • Analogue meters: ±5% of reading (depends on meter)

High Voltage Testing (HV withstand, insulation tests, insulators, etc)

to Standards

  • AS 1931.1
  • IEC 60060-1
  • AC voltages up to 100 kVrms at 50 Hz, with 20 kVA supply capacity
  • AC voltages up to 300 kVrms at 50 Hz, with 3.6 kVA supply capacity (resistive load) or 7.5 kVA (capacitive load)

Puncture/Withstand Testing:

  • up to 5 kV/AC/DC ay 125 VA
  • up to 5 kV at 500 VA

Insulation Resistance testing (cable, motors, insulation, etc)

Test parameters:
  • Insulation Resistance
  • Polarisation Index (PI)
  • Dielectric Absorption Ratio (DAR)
  • Dielectric Discharge Indicator (DD)
  • Step Voltage (SV)
  • at voltages up 5 kV d.c.
  • from 1 MΩ to 100 GΩ

High Voltage Operating Sticks

ISSC14-Chapter 13

Guide to Electrical Workers Safety Equipment-Industry Steering Safety Committee

  • Inspection
  • High Voltage Withstand and Leakage Test (microamperes) at 45 kVrms per each 300 mm section

FIELD CAPABILITY

High Voltage Voltmeters/Dividers

Calibration:
  • DC: (+ve or -ve) up to 90 kV
  • AC rms: up to 70 kV , 50 Hz to 400 Hz
Least Uncertainties:
  • DC: ±2.5% of reading or ratio
  • ACrms: ±5%

X-ray Dividers (medical, scientific)

As above for HV Voltmeters/Dividers

Insulation Resistance testing (cable, motors, insulation, etc)

Test parameters:
  • Insulation Resistance
  • Polarisation Index (PI)
  • Dielectric Absorption Ratio (DAR)
  • Dielectric Discharge Indicator (DD)
  • Step Voltage (SV)
  • at voltages up 5 kV d.c.
  • from 1 MΩ to 100 GΩ