Sonel S-36 VLF, User Manual

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S-36 VLF
– USER MANUAL
7
2 Overview and functions
2.1 Design of the set
The Cable Test Set S-36 VLF consists of the operating unit and high-voltage unit.
The high-voltage unit accommodates the following oil-insulated devices: high-voltage transformer,
high-voltage switch, rectifier, measurement divider and discharge device. The bottom region of the unit
contains an oil-to-air heat exchanger with forced circulation.
Both devices of the unit are connected by a control cable, which is permanently connected to the
operating unit.
Fig. 2.1 View of high-voltage unit (left) and operating unit (right)
2.2 Functionality
For operating the device, the operating unit and the high-voltage unit must be properly grounded.
The unit is provided with an internal grounding safety circuit which allows the unit to be operated only if
a sufficient low-resistance connection exists between the protective ground and station ground.
The device has a number of further protective functions such as mains voltage monitoring and
power-on disable if a residual or external voltage is present at the output. Only when all specified pa-
rameters are met, the high-voltage can be turned on.
The design provides for redundancy of all important safety functions.
In the
high-voltage unit , the test voltage is generated by means of a high-voltage transformer,
rectifier and high-voltage switch. This voltage may either be a low-frequency alternating voltage
(0.1 Hz) or a direct voltage of positive or negative polarity.
On completion of a test or tripping of a protective device, the connected equipment under test is
also automatically discharged via the discharge device, which is also integrated in the high-voltage
unit.