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AC Dielectric Strength Systems

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The system allows to verify the dielectric strength of the cables at the end of their production to verify the goodness of the insulation. It is carried out at a certain voltage and for a certain time, imposed by the reference standards, by the specifications of the customer or the certification body.

The alternating current test is accepted and recognized as official by the various institutions and institutes of the quality mark of the various nations.
Usually the system is installed in an adequately prepared area of the company with all the safety systems, following the instructions provided with the system.

 

SIF studies and designs the most suitable technical solution in a customized way based on customers’ different needs and paying attention to:

DIMENSIONING THE POWER OF THE SYSTEM

It is very important to size the transformer power according to the test voltage, the capacity value of the cables and of the quantity of bobbins to be tested at the same time, and the future needs.

To make the most of the power of the transformer, SIF provides solutions with the possibility of selecting multiple voltage scales to provide a higher test current at lower voltages. This allows you to economize the system and at the same time try an adequate number of bobbins

 

SYSTEM AND FENCES LAYOUT

We offer our customers LAY-OUT DESIGN service of the plant and the enclosures, developed on the area test indicated by the client, applying our skills and experience to simplify the installation of the system and the realization of the protections to ensure the safety of the operators. It is possible to work on several test boxes to speed up the tests.

ACCESSORIES NEEDS

During system study, the customer may need accessories (high voltage knife switches - earth connectors, certified measurement transformer, stand-off insulators, bushing insulators, gates earthing pliers) or to integrate the system with the commutation tests or with a detection system of the faulty bobbin.

NECESSITY OF SPECIFIC TESTS AND COMPLIANCE WITH STANDARDS

Our test system are compliant with standards CEI EN IEC 61010-1, CEI EN 50191. The customer may need to respond to other types of standards with specific testing needs.

 

The real added value of the equipment, are the innovative solutions born from the inventiveness of the Research & Development team, which has been able to combine creativity and engineering, to:

  • INCREASE THE TEST PERFORMANCE
  • GUARANTEE MAXIMUM SAFETY
  • SIMPLIFY THE USE OF THE SYSTEM

Through a PLC control system and a SIEMENS color graphic touch screen display, there is the possibility to set different functions like:

  • the test parameters such as voltage and duration time
  • select the test scales
  • select the test box
  • perform the test in automatic or manual mode

 

Already included in the system:

  • Regulation automatism up to the set voltage
  • Automatic start of the test time when the test voltage has been reached
  • Maximum current thresholds on the primary circuit, on the secondary circuit with adjustment to the current range and software tracking threshold.
  • The completeness of the equipment already provides on board a coordinated management system of the security connected to the test enclosures protection and signaling to protect the operators.

Composition and characteristics of the test system

TRASFORMER

Test Voltage up to 100 kV available
Test power up to 300 kVA available
Continuous service with natural cooling in air or oil
Ground connected pole

Options:

• Up to 4 high voltage sockets available, at maximum power, switchable on a single output to test multiple cable bobbins at the same time

• Version with Motorized High Voltage Switch.

INTEGRATED POWER CABINET WITH VOLTAGE VARIATOR

Test power up to 150 kVA for continuous service
Sectioning and power commands
Emergency Button
Automatism and remote commands
Double amperometric circuit.

Option:

Phase correction reactors for powers above 150kVA

 

COMMAND BENCH

Auxiliary services with key switch and emergency button
SIEMENS PLC for the management of automatisms including the personnel safety ones
9” SIEMENS Touch Screen Graphic Color Display for settings of functions and test parameters as well as signaling.
Test Voltage and Current measurement.
Time counting.
Auxiliary circuits for external signals of voltage danger, with preventive and simultaneous insertion with auxiliary services.

 

 

Test system accessories

PNEUMATIC KNIFE SWITCH - EARTH CONNECTOR exclusively made by SIF

It allows you to disconnect the high voltage transformer and ground the cable at the end of the test to discharge the residual current. To further increase safety, the system has been designed with a pneumatic circuit in such a way that ground cable discharge is guaranteed even in the event of an electrical malfunction. Thanks to this device it is possible to work in safety on several fences at the same time and to reduce the times for the preparation of the cables under test.

 

STAND OFF INSULATOR

To ensure adequate isolation of the test voltage distribution inside the boxes.

 

BUSHING INSULATOR

To ensure adequate insulation for the connection between the area where the transformer is located and the test area.

 

VOLTAGE MEASUREMENT TRANSFORMER

Isolated in air or in oil depending on the maximum voltage to be measured.

 

DATA ACQUISITION SOFTWARE

Test data acquisition software with possibility to export data in a standard format.