Typically HVCC, HFCT or Rogowski coils are installed on each phase, with sensors brought to a terminal box housed close to the surge pack, cable termination box or machine terminal areas. HVCC sensors are in the range 80pF – 9nF (80pF, 145pF, 500pF, 1nF, 2nF, 9nF are common values). BNC connections are common, however in some cases terminal blocks or TNC connections may be used.
TEV and acoustic sensors may be permanently installed on switchgear cubicles. TEV sensors normally have BNC connections in terminal boxes, rail-mounted in LV compartments or as a bulkhead connection on the side of switchgear.
VDS ports installed for voltage presence indication are also utilised for PD detection, typically with connection to banana plugs ports.
Airborne acoustic sensors may be installed; often these have a proprietary interface to connect to a specific instrument.
HFCT sensors may be permanently installed at cable terminations. HFCT sensors normally have BNC connections (N-type and TNC are also used). Connections are made in a terminal box, rail-mounted in LV compartments or as a bulkhead connection on the side of switchgear.
VHF/UHF sensors may be installed at terminations and joints with routing to a termination box. BNC, TNC or N-type connectors are used. HFCT sensors may also be used at cable terminations or at joints with attachment at earth link boxes or earth sheath cross-bonding points.
UHF couplers are often permanently installed from original equipment supply. N-type connectors are common, with TNC and BNC also used. The connection points may be inside a terminal box where the coupler is installed, routed to a common connection point or an exposed connector with a dust cap on the side of switchgear.
Bushing tap sensors are attached to test taps or voltage taps at the base of high voltage bushings. The sensor outputs are routed to a terminal box close to ground level. UHF sensors may be installed on hatches as part of the equipment supply; these generally have N-type connectors with a dust cap or within a terminal box.
Book a PD test using your existing sensors.
The presence of permanent PD sensors can often be identified on layout drawings and verified with visual inspection at site. PD couplers may come from the OEM or third party sourced including: HVPD, Monitra, Adwel, Alstom Pamos, Condis, Dowding and Mills, Eriks, Iris Power, Qualitrol, Sulzer.
