The most reliable distribution system is one that can eliminate customer outages, not just limit threats. Trayer’s auto transfer switchgear allows for, in a single unit, an uninterruptible primary power feed switching solution without the cost associated with alternatives. With this system, switchgear can be configured for both spot and loop-feed systems.
A smart ATS features integral control and sensing for automatic source selection. Control logic is user configurable and can be programmed for traditional ATS operation so that a preferred power Source normally feeds the load. If preferred power is lost (loss of voltage sensing), the ATS will automatically disconnect from the preferred source and then connect the alternate power Source to the load.
This traditional ATS control function reacts to a loss of Source voltage, and although power to the load is quickly restored, the load always experiences a power outage.
An ATS can also be programmed for uninterruptible power delivery. Figure 1, illustrates a typical ATS circuit configuration. However, the ATS source connection is via Vacuum Fault Interrupters (VFI); both VFIs are normally closed, so that the load is fed from both Sources continuously. This presents a very “stiff” power Source to the load, and greatly reduces voltage sag and voltage flicker for improved Power Quality.
In Figure 2, one of the Source Feeders experiences a fault. An ATS with configured logic detects overcurrent flowing towards the fault and automatically trips open that Source VFI to disconnect from the faulted circuit. Then, the Substation breaker opens from overcurrent. Note that the other (connected) Source continues to feed the load, and the load does not experience a power outage. Once the Feeder voltage is restored, the ATS automatically closes the open Source VFI, returning to normal switch condition.
A smart ATS is ideal for critical customer loads, where power outages are prohibitive. The dual functionality (ATS or Uninterruptible mode) assures that switchgear will meet any critical load requirement.
Trayer premium power switchgear is also available for Distribution loop systems; perfect for Urban grids, Industrial parks, Petro/chemical facilities, Military and Institutional applications.
Contact your local Trayer Sales Representative and visit our Web page for more about Trayer uninterruptible power Switchgear.