Description

The PDC Series Partial Discharge Sensor-Coupling Capacitor is a sensor used for online and offline partial discharge measurements on rotating machines. Each sensor is a high voltage capacitor with an integrated quadrupole.

Permanent or temporary partial discharge monitors can be connected via standard RG58 BNC cables to the couplers, usually by using a termination box in between. The PDC-1000 series has an integrated high voltage cable which will be connected via cable lugs to the high voltage busbars of the rotating machine to pickup partial discharge signals without any loss. A specially designed measurement impedance located in the base of the sensor allows to pick up partial discharge signals as well as the line frequency (1:2000). This allows us to transfer partial discharge signals and line frequency signal over the same cable to the partial discharge detector. The Signal output is protected via 90V surge arrestor. The shield of the coaxial output is capacitive floating to avoid eddy currents in the signal cables due to high magnetic fields.

The frequency range that the coupling capacitor operates within is the combined result of the capacitance value and the impedance value provided by the quadrupole.
–   A high capacitance value (1000pF) results in a lower frequency range.
–   A low capacitance value ( 80pF) results in a higher frequency range.

Most major generator manufactures recommend that partial discharge activity should be measured in the low frequency range. For this reason we offer the 1000pF Coupling Capacitors.
For those customers who prefer to measure partial discharge activity in the lower frequency range we also offer the 80pF version.

The PDC Series Coupling Capacitors are fully compliant with the IEC-60270 and IEC-60034 standard and are available at different operating values: 7kV, 12kV, 17.5kV, 24kV.

Key Features Comparison Table

Partial Discharge Coupling Capacitor for 7kV rms@1000pF

• Nominal Voltage: 7kV rms
• Capacitance: 1000pF
• Frequency Range: 50/60Hz
• PD Level @ Un: < 5pC
• Voltage Divider: 1:2000
• Signal Output Type: BNC female
• Withstand Voltage (1min): 23kVrms
• Operating Temperature Range: -20 .. +125°C
• Built in Quadrupole with voltage reference output
• Built in Overvoltage protection
• Capacitive floating signal output to avoid Eddy current loops

 

Partial Discharge Coupling Capacitor for 12kV rms@1000pF

• Nominal Voltage: 12kV rms
• Capacitance: 1000pF
• Frequency Range: 50/60Hz
• PD Level @ Un: < 5pC
• Voltage Divider: 1:2000
• Signal Output Type: BNC female
• Withstand Voltage (1min): 32kVrms
• Operating Temperature Range: -20 .. +125°C
• Built in Quadrupole with voltage reference output
• Built in Overvoltage protection
• Capacitive floating signal output to avoid Eddy current loops

 

Partial Discharge Coupling Capacitor for 17.5kV rms@1000pF

• Nominal Voltage: 17.5kV rms
• Capacitance: 1000pF
• Frequency Range: 50/60Hz
• PD Level @ Un: < 5pC
• Voltage Divider: 1:2000
• Signal Output Type: BNC female
• Withstand Voltage (1min): 45kVrms
• Operating Temperature Range: -20 .. +125°C
• Built in Quadrupole with voltage reference output
• Built in Overvoltage protection
• Capacitive floating signal output to avoid Eddy current loops

 

Partial Discharge Coupling Capacitor for 24kV rms@1000pF

• Nominal Voltage: 24kV rms
• Capacitance: 1000pF
• Frequency Range: 50/60Hz
• PD Level @ Un: < 5pC
• Voltage Divider: 1:2000
• Signal Output Type: BNC female
• Withstand Voltage (1min): 61kVrms
• Operating Temperature Range: -20 .. +125°C
• Built in Quadrupole with voltage reference output
• Built in Overvoltage protection
• Capacitive floating signal output to avoid Eddy current loops