FTB/FTP Advantages

FANOX FTB/FTP test block allows testing the protection, control, metering and/or communication device of a facility connected to field switchgear, easily and safely, isolating the circuits fully and eliminating all risks for the user.

  • Maximum safety for the user.
  • Internal automatic CT short circuiting.
  • Single hand fully isolated plug.
  • Locking system for safest operation.
  • Possibility of horizontal or vertical mounting, respectively.
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    14 circuits with different possible configurations (trips, current, voltages).

    • Safe for the user, who will never have access to live parts during insertion and removal operations.
    • Safe sequence of disconnection. The circuits of the trips open first, avoiding undesired operations, and then the voltages and currents, ensuring that the transformer circuits on the field side have been shorted before the separation of the circuits from current (make before break sequence).
    • Safe sequential removal of the test plug, connecting first VTs and CTs, and using a braking system allowing the relay to stabilize before connecting the tripping circuits.
    • Single Test Plug for all the different variants of Test Blocks.
    • During insertion and removal operation there will be no bounces which can cause interruption of the CT circuit.
    • Versatility for the user who can choose the most appropriate options for its application.

    FANOX FTB test block includes 14 circuits, which can be accessed by removing the front cover. Each of these circuits is connected to a separate pair of terminals at the rear of the case, and comprises a contact which is normally closed when the equipment to isolate is in normal service.

    There are different types of possible circuits (trip & signals, voltage, current), and each of the circuits of the FTB test block can be configured to be of a determined type. In case of current circuits an automatic short circuit mechanism is included to ensure the CT circuit is short-circuit before the contact in the test block opens.

    Two different types of short-circuits will be allowed: short-circuit of two circuits and short-circuit of four circuits, according to the application. By the product ordering code the user will specify number of circuits of each type, the position of these circuits within the test block, and also the type of short-circuits required for the current circuits. All the current circuits will be marked in a different color to allow easy identification, which will be visible even with the test plug inserted.

    During the insertion of the test plug, the circuits are prepared for testing, in the following sequence:

    1. Opening of tripping & signal circuits
    2. Short-circuiting the CT’s
    3. Opening of current & voltage circuits

    Once the test plug is connected, the protection relay is prepared for injection tests, which will not affect at all to the rest of the system, from which it has been safely isolated Field elements will be automatically isolated short-circuiting current circuits and opening voltage and digital circuits.

    The rugged FTP test plug includes a mechanism to guide and facilitate the insertion on the test block ensuring the opening of all contacts at the same time, and the insertion in the correct position. Once the test plug is inserted, it is possible to block it mechanically so that not involuntary extraction could be done.

    The test plug includes 28 sockets which allow the use of safe banana plugs. 14 sockets are for injection test on the protection relay, and 14 for accessing to live side. Protection side and live side are clearly marked on the test plug. Each socket on the test plug is identified by a number which coresponds to the same numbered terminal of the test block to which the socket is connected when the test plug is inserted.

    When the test plug is removed, a retention system will oblige to make this removal in the following sequence:

    First step:

    1. Connection of voltage & current circuits.
    2. Opening the short circuit of the CTs.

    Second step:

    1. Connection of tripping circuits.

    Before proceeding to the second step, it is necessary to act on the retention system of the test plug. This operation will give the necessary time for the values of current and voltage to stabilize after energizing transients, avoiding thus unwanted tripping due to these transients. During insertion and removal operation there will be no bounces which can cause interruption of the CT circuit.