Voltage detection in MV switchgear
March 2012
Electrical Power & Protection
Integrated voltage indicator with relay output.
The Vois R+ from Kries is an integrated capacitive voltage indicator according to the IEC 61243-5 standard for voltage detecting in medium voltage switchgear. The change from voltage present to voltage absent is indicated by a change in the arrow symbol on the front panel, from visible to invisible, and can also be monitored via the integrated relay outputs. The device needs no power supply to indicate the voltage, the energy necessary for indication is taken from the capacitive coupling and power is only required to drive the relay outputs.
The safety rules and laws dealing with working on medium voltage equipment and the five safety rules according to DIN -VDE 0105 have to be observed. Independent of the indication on the Vois R+, the earthing switch must be switched on before opening the switchgear or working on live parts. Vois R+ is suitable for connecting to specified capacitive coupling electrodes. The coupling part which is connected to Vois R+ must meet the interface conditions according to IEC 61243-5.
For testing voltages higher than 15 kV and frequencies lower than 16 2/3 Hz, the three-phase connecting point on the front has to be short circuited. The three-phase connecting point is adapted to the LRM conditions according to IEC 61243-5. The connecting point is suitable for testing phase comparison, phase sequence, redundancy, and as an option, maintenance testing. For this purpose Kries offers the universal CAP-Phase combined voltage detector and phase comparator.
Vois R + is suitable for use in an operating temperature range from -25 to +55°C and meets IP54 protection requirements.
For more information contact Johan van Staden, Surgetek, +27 (0)11 792 1303, [email protected], www.surgetek.co.za
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