High Voltage Construction Kit

 

 

Test room

A suitable test room is required to accommodate the High Voltage Construction kit,a floor soace of 3 X 4 m is recommended,and a favourable height is 2.5 to 3 m. The space requirements for a three-stage configuration are determined by the impulse voltage test equipment by the impulse voltages in excess of 1000 V are generated,the safety regulations of VDE 0104 must be met for test equipment in Germany.In other countries, the local safety regulations apply. For a good test room,screening and grounding are essentials.

Safety equipment

The test area shall be enclosed by a metel fence of at least 1.8 m in height,the mesh width not to exceed 50 mm

All doors leading into the test room must be equipped with door contacts.The contacts are closed when the door is closed.All contacts shall be connected in series and fed ti the appropriate sockets on the control desk.

Even with only one door of the test room being open,the test equipent cannot be energized,the secondary contactor will disconnect the circuit immediately.

Red and green warning lamps shall be installed on all doors leading into the test room.these lamps are to be connected to the appropriate terminals of the control desk.

The warning lamps indicate the following conditions:
a) Green=Ready for operation (control voltage switched on)
b) Red=Danger (primary contactor, secondary contactor switched on)
c) No indication- position unknown (Same as Red=Danger)

Screening

Comonents of the High Voltage Contruction Jit can be used for partial discharge measurements.the test transformer TEO 100/10,the measuring capacitor CM and the other components required are,in a proper set-up,practically free from partial discharges.To ensure the good performance of partial doscharge measurments without disturbence from external HF sources, metal fences (rfer to "Safety Equipment")are no longer satisfactory. The test room must be screened.Walls, ceiling and floor must be lined with metal.This lining can be made either of double mesh wire with a mesh size smaller than 10mm or of copper foil of 0.1...0.2 mm thickness. the edges of the individual metal sheets must be joined very carefully to obtain a high degree of conductivity.It is recommended to sew and soft-solder the mesh wire and to soft-silder or fold several temes the edges of the copper foil.

Welded or soldered joints should be given preference to screw or clamp joints.

The floor should preferably be covered with non-skid sheet metal(goffered plate).THE Individual sheets should be joined by welding and a good conductive connection be made to the ceiling and wall linings.

All cables fed into the test room should enter the Faraday cage at a central point.The test transformars lead can be equiped with the commercially available bushing filters which will prevent HF disturbances from entering the test area through the lead.

Earthing

It is expendient- and a must for impulse voltage test equipment- to use low-inductance connections(e.g. copper bands 100 mm X 0.6 mm),which connnect all components of the high-voltage circuit that must be earched to ONE earth terminal.Parts of the installation which do not belong to the high-voltage curcuit(e.g. metallic safety fences) and the earth leads of the discharge rods or grounding switches shall also be connected to the earth terminal,which is insidethe safety enclosure and reliably connected to the earthing system (e.g. deep earth rod).