High Voltage DC Dielectric Test Sets
The High Voltage DC Dielectric Test Sets (70, 120 and 160 kV) provide the most dependable, portable dc highvoltage sources for checking the quality of electrical power cables, motors, switchgear, insulators, transformers and capacitors. Each portable set (heaviest is 73 lb, 32.8 kg) is comprised of two separate modules:
Control Module
This module allows the operator to switch-select the appropriate current output range, adjust the output level and monitor both the applied voltage and leakage current at a safe distance from the high voltage being delivered to the load under test. No voltage higher than input ac power is present in the control module.
High-Voltage Module
An air-insulated design receives its instructions from the control unit. It generates the dc high voltage that is delivered to the load under test. Although a different control module is used with each of the three models, they are all the same size and weight. Each high-voltage module is a different size and weight to accommodate the rated output voltage.
Time-varying tests such as the polarization index test (PI test) are independent of temperature effects and save time. To perform this test, a predetermined test voltage is applied to the unit under test and readings are taken at 1 minute and 10 minutes. The resulting ratio is analyzed to determine insulation quality. This type of test is especially appropriate for high-capacitance samples.
The step-voltage test is independent of temperature effects and saves time. To perform this test, the output voltage is increased in even steps at regular intervals over a fixed period of time. As long as the resistance of the unit under test increases with time, it has high-quality insulation. This type of test is only useful for high-capacitance samples.
Features:
- Operates Like a Full-Wave Rectified Unit (Filtered Half-Wave
Rectification)
- Provides the advanced performance equal to a full-wave rectified unit.
- Allows for a simple circuit scheme for long-term reliability.
- Lightweight High-Voltage Module
- Air insulated, it is the lightest weight module available for its voltage
and power ratings.
- Convenient portability allows a single operator to transport it into the
field.
- Complete Internal Guard Circuit/Guard Connection on High-Voltage Output
Cable
- Intercepts stray surface leakage currents which could interfere with the
measurement.
- Eliminates the need for an extra lead to hook up the guard connection.
- Ensures highly accurate measurements.
- Choice of Digital or Analog Metering
- The preferred medium may be selected by the user.
- Continuously Variable Test Voltage
- User can set test voltage to intermediate values as required.
- Fast Charging of High-Capacitance Samples
- Saves the operator test time.
- Negative Polarity to Ground
- Applies a worst-case condition to assure reliability.
- Strip Chart Recorder (Optionally Available)
- Provides a permanent record of the leakage current for the unit under
test.
- Standard Safety Features
- Bipolar ammeter that displays the magnitude of the discharge current
from the unit under test (digital models only)
- Input-supply-line circuit breaker
- Output current overload relay
- Zero-start interlock for high-voltage output
- Pushbutton controls and indicating lights for high-voltage ON/OFF
- Full circuit-breaker protection against internal damage by overloads,
surges or test sample breakdown
- Connection for external permissive and safety interlocks
- 160-kV DC Dielectric Test Set
- Acceptance testing on 46 kV class cable
- Maintenance testing on 115 kV class cable
