High Voltage Dividers are
used to reduce high voltage signals to levels which
can safely be measured by either conventional multimeters or specialized
instruments such as oscilloscopes, peak voltmeters or digital
recorders/analyzers. These dividers are available in different
designs. The divider type depends on the voltage waveform to be measured.
Type of
Dividers
Four types of dividers are available (which measure different waveforms)
- AC voltage dividers
- DC voltage dividers
- impulse voltage dividers
- combined, je, AC & impulse or AC,DC & Impulse
Divider
Construction
From the construction point of view the
following designs are used for dividers:
- capacitive design
(C): suitable for AC and switching impulse voltages
- damped capacitive (RC): suitable for AC, lightning & switching
impulse voltages
- resistive (R): suitable for DC voltage (high resistance - Meg Ohm)
and lightning impulse (10w resistance - k Ohm)
- parallel R damped capacitive (RCR): suitable for AC, DC, lightning
& switching impulse voltages
Voltage divider
components
- high voltage arm (one or more
sections in series)
- low voltage arm (secondly unit)
- measuring coaxial cable and termination
The high voltage and low voltage arms
are usually mounted together on a base (fixed or
mobile). The termination is placed at the end of the coaxial cable and
it may have several
outputs for several divider ratios.
Typical Voltage
Ratings
The following table shows typical
nominal voltage ratings of one section of the high
voltage arm. One or more sections in series may be used, depending on the
amplitude
of the measured voltage.
|
Divider Type |
Section
Nominal Voltage (kV) |
| |
AC |
DC |
Lightning
Impulse |
Switching
Impulse |
|
capacitive (C) } |
60 |
|
|
120 |
|
damped capacitive(RC) |
60 |
|
175 |
120 |
|
resistive (high resistance-MOhm) |
|
100 |
|
|
|
resistive (low resistance -kOhm) |
|
|
200 |
|
parallel R damped
capacitive (RCR) |
60 |
100 |
175 |
120 |
Features
- compact, lightweight
and mobile design
- designs available to measure AC or DC or impulse (switching,
lightning and steep front) or a combination of several voltage
types.
- internal compensation to minimize oscillations during impulse
measurements
- indoor voltage divider that can be retrofitted for outdoor use
- individual HV sections are stackable to accommodate the desired
voltage
- custom made ratings, ratios and input/output impedances available
- maximum rise time of 20 ns and minimum impulse response time of 35
ns with less than 15% overshoot available
Applications
Voltage dividers are
suitable for:
- laboratory use in universities, research and high voltage
facilities
- assembly line or product approval testing in manufacturing plants
- outdoor short and long term field measurements on electrical
systems
- use with fiber measuring systems
Design
- the High Voltage housing
is comprised of electrical grade fiber glass tubes.
- transformer oil or SF6 insulating gas can be used as the insulating
medium.
- capacitors are of either oil-paper or solid dielectric design.
- external polymeric housing and sheds can be added for outdoor use.
- the secondary circuit incorporates temperature stable resistors and
capacitors, arranged in a coaxial design.
- BNC, LEMO or RF connectors are available.
|
Typical Specifications
A. Electrical
- 60 kV rms continuous
- 100 kV DC continuous
- 120 kV switching impulse
- 175 kV lightning impulse
- 200 kV steep front impulse
B.
Mechanical/Physical
- 120 mm diameter
- 1.5 m height (incl. base)
- 15 kg weight (SF6 filled) |
Ordering Information
- Type
of divider
- Nominal voltage rating
- ratio
- input and output impedance
- step response and rise time
- cable connector type
- cable length
- indoor or outdoor use
- insulating medium (oil, SF6,resin)
- stationary or mobile base |
|
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