Atec 220072 User Manual
70-, 120- and 160-kV DC
High Voltage DC Dielectric Test Sets
■
Available in analog and digital models
■
Lightest weight available in air-insulated
high-voltage model
■
Advanced performance with long-term
reliability provided by filtered half-wave
rectification
■
Designed for maximum operator safety
70-, 120- and 160-kV DC
High Voltage DC Dielectric Test Sets
DESCRIPTION
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.
APPLICATIONS
The dc dielectric test sets are used to make proof tests and
insulation tests on electrical power cables, motors,
switchgear, insulators, transformers and capacitors. Both
types of tests are performed by applying controlled high
voltages to the unit under test at or above insulation
system operating level. Measuring the leakage current
helps determine the unit under test’s ability to withstand
overvoltages such as lightning strikes and switching surges.
The three models described cover a range of output
voltages that meet the most commonly specified ratings
in5-kV to 69-kV class cable. All are suitable for testing
power cable, switchgear and rotating machinery in
accordance with IEEE, IPCEA, NEMA and ANSI guidelines.
Proof Test
Proof testing is used for acceptance testing of newly
installed cable and maintenance testing of aged and/or
repaired cable. For the proof test, the unit under test will
either withstand the test voltage or it will “break down,”
providing the user with a “go/no-go” answer.
Insulation Resistance Tests
To make appropriate tests on healthy insulation, the test
instrument must have microampere sensitivity. Insulation
resistance can be measured in at least three different ways:
The insulation resistance test is often referred to as a “spot
check,” and is performed by applying a predetermined
voltage to the unit under test, holding it until the apparent
leakage current becomes stable and recording the readings
with adjustments for temperature. This test is especially
applicable to low-capacitance units under test.
Digital Model, Cat. No. 220070
Front panel of Analog Model, Cat. No. 220124
70-, 120- and 160-kV DC
High Voltage DC Dielectric Test Sets
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 AND BENEFITS
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
Model Capabilities/Applications
Following are the acceptance and maintenance
testing capabilities of each of the dc dielectric test
sets.
70-kV DC Dielectric Test Set
■
Acceptance testing on 15 kV class cable
■
Maintenance testing on 28 kV class cable
120-kV DC Dielectric Test Set
■
Acceptance testing on 35 kV class cable
■
Maintenance testing on 46 kV class cable
160-kV DC Dielectric Test Set
■
Acceptance testing on 46 kV class cable
■
Maintenance testing on 115 kV class cable
SPECIFICATIONS
Input Power
Nominal 120 Vac, 50/60 Hz
For 220/240 Vac, 50/60-Hz operation, add –47 to Cat. No.
Please note that specifications for the –47 models differ as
follows:
Output Current: 220/240 Vac
120 kV Models: 5 mA for 5 min; 2 mA continuous
160 kV Models: 5 mA for 5 min; 1.5 mA continuous
When using external 240/120-volt step-down voltage transformers,
the ratings may be used as given for 120 volt input.
Weight: Add approx 2 lb (1 kg) for –47 control unit.
Ammeter (Digital Models)
Ranges:
0 to 19.9 µA
0 to 199 µA
0 to 1.99 mA
0 to 5 mA
Resolution: To 0.1 µA on lowest range
Accuracy: ±2% of reading + 1 digit
Ammeter (Analog Models)
Ranges:
0 to 5 µA
0 to 50 µA
0 to 500 mA
0 to 5 mA
Resolution: To 0.1 µA on lowest range
Accuracy: ±2% of full scale range
Voltmeter (Digital Models)
Resolution: To 100 V over entire range
Accuracy: ±(2% of reading + 100 V)
Voltmeter (Analog Models)
Resolution — Dual Range:
35 kV/70 kV: 2.5% full scale
60 kV/120 kV: 1.6% full scale
80 kV/160 kV: 2.5% full scale
Accuracy: ±2% of full scale range
Loading...