Capacitive ac voltage dividers

APPLICATION
The capacitive voltage measuring dividers are used to convert the high AC voltages from RMS voltages up to 1200 kV into a measurable and processable value for voltmeter.
The performance of a capacitance divider is mainly determined by the stability of the high- voltage circuit.
Dividers are designed to fulfill all requirements of IEC standard 60060-2.
The divider can be realized to be used also as coupling capacitors for PD measurement.

GENERAL DESIGN
The high-voltage capacitor is made of single units of solid polypropylene capacitors immersed in oil.
Single capacitor packages are connected in series with the inserted damping resistors. The components are housed in fiber-glass cylinders with metal flanges.
For higher voltages several high-voltage capacitors are connected in series. The low-voltage capacitor is located at the lower end of the capacitor column.
Its compact and coaxial design and its parallel configuration of low-voltage capacitors, provides a very low inductance value and high protection against electrical noise.
The termination resistor for the connection of a 75 Ω measuring cable (triaxial) is included.
The divider has to be connected to a high-impedance measuring system (voltmeter ≥ 1 MΩ, ≤ 100 pF).
On the low voltage capacitor branch is located the earthing terminal that is realized with 2 metallic plates to optimize the connection to the earth through copper strips.
The capacitor column, if necessary, is mechanically stabilized with a bracing realized with fiber-glass rods.
At the top of the capacitor column there is the top electrode that as standard is realized with as double toroid.
The divider can be equipped with additional taps for partial operation. This item allows the optimum adaptation to the relevant test voltage level.
The top electrode is designed and optimized for the rated voltages 50/60 Hz.

ROUTINE TESTS AND TYPE TEST
A.M.E. certifies the divider performance by different internal test and calibration procedures according to IEC 60060-2. In addition to the internal test report, A.M.E. can provide an official calibration certificate issued by the Italian Metrology Research Center INRIM

 

ELECTRICAL MAIN PARAMETERS

01tab Electrical

 

SCOPE OF SUPPLY
Impulse voltage measuring consisting of:
• High-voltage capacitor
• Base frame with wheels (air cushions under request)
• Low-voltage capacitor mounted on base frame
• Measuring cable (Z = 75 Ω, l = 15÷35 m)
• Connection point for high voltage and earthing connection
• Top electrode designed for AC 50/60 Hz rated voltage
• Bracing with fiber-glass rods, if necessary
• Technical Documentation
• Maintenance user manual
• Calibration Certificate

 

OVERALL DIMENSIONS AND WEIGHT

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OPTIONS
• Adaptation to other output low voltages
• Usage as coupling capacitor for PD test (PD level <2 Pc at VN)
• Air cushion instead of wheels
• Other lengths of measuring cable
• INRIM calibration certificate

 

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