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Test Interfaces for Power Systems



The FTL is a test block for interfacing substation devices (protection relays, fault recorders, revenue meters, ... ) to the voltage and current transformers and to other equipment on the system side of a power grid.

The FTL test block uses disconnect pins to isolate the substation devices from the system side equipment. Once isolated, secondary injection can be performed using banana jacks on the front side of the test block.

Key Features

  • Finger-safe
    There are no exposed metallic parts on the FTL test block, greatly increasing safety during testing. Even the back-side is finger-safe.
  • Keyed Disconnect Pins
    Disconnect pins are keyed to the corresponding slots of the test block, preventing mistakes and errors during test.
  • Less than 2 mΩ internal resistance
    Thanks to the patented construction, FTL test blocks have an extremely low internal resistance. This decreases the burden placed on instrumentation transformers and also reduces heat dissipation inside cabinets and panels.
  • Over 100 Models and Counting
    Models with 8, 10, 12, 14, 16, 18 or 20 poles. Any combination of currents, voltages or trip signals. Custom labeling. The right FTL test block either already exists or can easily be created.
  • Ideal for Retrofit of Older FT Switches
    The 10-pole models use the same panel cutout as the older FT switches. Even the terminal labeling is the same. That means that you can have the increased safety and efficiency from the FTL without having to change your engineering drawings.

Principle of Operation

Closed circuit
A FTL test block contains 8, 10, 12, 14, 16, 18 or 20 modular units (or poles) each allocated to a current, voltage, signal or trip circuit. Each circuit is connected through the block via two silver-plated copper contacts, pressed securely together by two pressure springs to create a highly conductive electrical connection. In this situation, a electrical connection is established between the device side (B) and the system side (A).
Open Circuit
To open one of these modular poles, a disconnect pin is removed from its inactive "parking" position and inserted between the silver-coated copper contacts (the "test" position). In this position, the device and system sides of the test block are isolated from each other. For current circuits, the disconnect pins include internal shorting bridges. When the pin is moved back to the "parking" position, the internal springs force the contacts back together, returning the circuit to its normally-closed position. There is no in-between position, completely eliminating the risk of accidents resulting from improperly closed circuits.
Signal Injection
When the disconnect pin is in the "test" position, a banana jack is accessible on the device side of the test block, allowing the connection of a test set and the associated signal injection. The banana jack on the system side is optional, but it is always accessible, if present.


Adapters for use with Insulated Banana Plugs
Allows the connection of test equipment with insulated banana plugs to the FTL test block (width of the insulated banana plug less than 11.5 mm)
Adapters for use with Wide Test Leads
This adapter is built for the connection of test equipment with relatively wide insulated banana plugs (width of 11.5 mm or more) to the FTL test block. One side of the adapter connects to the wide test lead and then connects via a short cable to a smaller banana plug that fits comfortably into the FTL banana jacks. The banana plug in the adapter assembly has a see-through plastic shielding that recedes when entered into the FTL banana jack.
Jumper Cable
This jumper cable allows the connection between 2 poles of the FTL test block. Both banana plugs of the jumper cable have a see-through plastic shielding that recedes when entered into the FTL banana jack.
Current Measurement Probe
This special test probe allows the connection of current measurement device or a shunt. The AWG 13 (2.5 mm) connection cable has a length of 118.11 inch (3 meters). The test probe are available with c-hook terminals or banana plugs at the tip of the cable.
FTL 19´´ Rack Plates
SecuControl offers metal plates for installation of FTL test blocks in 19” racks that come painted in various colors and with various cutouts for LTB test blocks, in standard heights of 2U or 3U.

Please consult our manual on the download section of this site for ordering information.



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