Kyle^® Type PST Pad-mounted Source Transfer packages are self-contained devices, which provide automatic source transfer in 6 cycles or less, and fault protection for 15, 25, and 35 kV underground systems. Critical customer loads, such as health, educational, financial, and manufacturing facilities, require optimum power quality and reliability. These loads are normally provided with a preferred and an alternate source of power. Source transfer packages are used to switch the load to the alternate source when the preferred source is lost, and to transfer back when voltage is restored.

PST combines several time-proven Kyle products into one package:

• The S control performs the automatic transfer based on loss of voltage detection. The Kyle Type S Control is a time-proven, user-friendly control that provides the timing and control logic required to perform the automatic source transfer. Simple relay logic and analog timers assure reliable operation, ease of installation and quick troubleshooting. The front panel of the control provides visual indication of the status of each CI interrupter, control settings, and manual operation capabilities. The S control can be programmed via the front panel, without the use of a computer.
• The TPG control provides fault detection. The Kyle Type TPG control provides overcurrent detection, and issues trip signals to the CI mechanism or the VFI mechanism depending on the PST configuration. The TPG control is powered by the current sensing transformers in the PST; no external voltage supply or battery backup is required. TPG is not affected by system voltage conditions such as overvoltage transients. A wide variety of time-current curves and settings are available for flexibility of coordination, and a SCADA accessory for remote control and monitoring. The TPG control can be programmed via the front panel, without the use of a computer.
• The CI vacuum fault interrupters perform three-phase switching and fault interruption. The CI interrupters feature Kyle patented, long-life maintenance-free vacuum interrupters, for many years of trouble-free performance. When energized, a motor winds the CI interrupter mechanism to charge the opening and closing springs; this provides quick-open and quick-close operation of the vacuum interrupters. This results in transfer times of 6 cycles or less. Each CI mechanism can also be operated manually, should control power be lost. A hotstick can be used to operate the trip/close levers, and the push-pull handles for manual charging of the springs. Viewing ports provide access to the contact position indicators and operation counters for each interrupter.

• The PST Model 6 is the industry standard. The PST-6 includes two CI mechanisms operated by an S control during loss of voltage conditions (transfer) and by a TPG control during fault conditions (tripping).
• The PST Model 9 includes two CI mechanisms operated by an S control during loss of voltage conditions (transfer) and two three-phase VFI (vacuum fault interrupter) mechanisms operated by two TPG controls during fault conditions. This arrangement provides independent transfer and fault protection operations of the PST when two critical loads are independently served from the same source.
  
  

  PST Switchgear Ratings
  Nominal Voltage	15 kV	25 kV	35 kV
  BIL (kV)	95	125	150
  Interrupting Current (sym.) (kA)	12	12	12
  Load Break and Continuous Current Rating (sym.)(Amps)	600/200	600/200	600/200

Automatic Source Transfer

PST
VACpac
VFI

Fault Protection

MOST
PWE, PWVE
RVAC
Shrubline VFI
VACpac
VFI

Switching/Sectionalizing

MOST
RVAC
VACpac

Controls

Type Tri-Phase and Tri-Phase  with Ground Trip (TPG)
Type S

Product Literature

Underground Distribution Switchgear Library

Product Applications

PST Automatic Source Transfer—The Ability in Reliability