Tescom STS 1000A 3 Pole, Руководство пользователя

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DESCRIPTION OF THE SYSTEM
The static transfer system provides a guaranteed means of switching between two alternative and independent
power sources thus ensuring a continued supply of power to any critical load. The switching can either be
AUTOMATIC should the incoming supply fall outside the predefined window of operation (user-defined), or
MANUAL should an operator want to force switching between the two input supply sources from the mimic
display panel or via a remote connection.
In the event of a failure of the source supplying the connected load, the load is automatically transferred to the
other available source.
The system provides following:
• Complete independence of two power sources and their respective distribution networks
• Redundancy for existing electrical equipment
• Separation of applications to avoid disruption caused by faults and failures.
For this reason the STS has redundant power circuits, with 2 power supply cards installed inside the STS.
The power supply cards are connected separately to all of the control cards, there means that the power
supply cards can be hot swapped, without disrupting the connected load.
The transfer between the two input power sources is always performed using a Break-Before-Make (BBM)
mode to guarantee complete separation between the two different sources, thus ensuring that they will never
be connected in parallel.
The STS is composed of two sets of SCR static switches, each of which is connected to a three-phase input source.
One of the two sources can be configured as the PREFERRED source (PS), and the other as an
ALTERNATIVE source (AS).
The output from each of the static switches is common and forms the device output.
Whenever the parameters of the source powering the load fall outside of the user-defined tolerances, either
voltage or frequency, the STS will automatically transfer the load onto the other source.
The transfer is completed with a maximum interval of one quarter of a cycle.
When operating in a Priority line mode, the user selects the input supply to which the STS will transfer the load
whenever its parameters are within the limits as defined by the user.
In order to keep transfers between the two sources to a minimum, the re-transfer onto the priority line once it
returns to within the accepted tolerance range can be inhibited, with the load being powered from the
secondary power source for as long as this source is considered to be good.
The STS will handle both sources as being equally acceptable as long as their parameters are inside the limits
of acceptable values, and therefore will not implement transfer back to a priority line.
The STS is available in three-pole and four-pole versions: the number of poles indicates whether the neutral
conductor is switched together with the phases (four-pole) or if the neutral line remains un-switched (three-
pole).
In either case, the neutral line (or lines) must always be connected to the STS (one for each source). In the
three-pole STS the neutral lines of the two sources are always connected together.
In the four-pole models, the neutral conductor is switched using an overlapping method
Make-Before-Break
(MBB) to prevent any voltage imbalance that could damage the connected loads.
The user can also execute a manual transfer from one power source to the other by means of the appropriate
command (SW6 switch).