Power Quality & Management

Sag Ride Through (SRT) Power Conditioner

Voltage sags occur frequently and can have a significant impact on plant operations and competitiveness.

A voltage sag is a sudden, momentary decrease in supply voltage. It can last from a cycle to several seconds. Voltage sags are most often caused by faults on the electrical distribution system. They can be caused by lightning strikes, animal contact, starting of large motors or an internal fault within a customer's facility.

In the United States, voltage sags cost billions of dollars in lost production, interruption, damaged materials, retooling and scrap. Protect your plant from costly voltage sags by installing Eaton's new Sag Ride Through (SRT) device.

Eaton's SRT is the first power conditioner to incorporate new technology that corrects voltage sags and maintains uptime and productivity. It corrects deeps sags down to 63% of nominal for single-phase sags (37% retained voltage), the most common type. The SRT responds within 1/8 of a cycle, corrects phase shifts and provides continuous voltage regulation.

The SRT is designed for low to medium voltage systems (600 Volts and below and up to 15kV for medium voltage applications) and is available in ratings from 25 KVA to 4 MVA. In addition, it requires no in-depth engineering study to select the appropriate model and requires no maintenance. Normally, a critical load profile and metering data review for site min/max load sag susceptibility is all that is required to select an SRT model.

The SRT offers customers higher performance than conventional voltage regulators.

SRT Features That Make the Difference

• Down to 63% voltage sag correction (single phase)
• Eliminates phase shifts - restores a balanced 3 phase output
• Cost-effective - typically pays for itself in less than 1 year
• Sub-cycle response - patented circuit enables 2 millisecond response (1/8 cycle)
• Continuous sag correction - survives multiple sag events and does not require time to re-charge capacitors
• 98% efficiency - ensures minimal operating costs
• Battery free - eliminates costly maintenance and disposal requirements
• On line design – provides 1% to 2% output voltage regulation for 10% voltage input deviations
• Small footprint - significantly reduces required floor space
• High Overload - withstands downstream faults or high inrush currents
• No minimum load - improves operating flexibility for fluctuating loads/process

SRT Technology
The SRT power conditioner is a series connected, voltage compensation device. The unit operates in an online mode and continuously monitors input voltage. When a sag disturbance is detected, the unit reacts in 2 milliseconds (sub-cycle) and electronically synthesizes the voltage required to correct the sag. The series connected transformer produces a clean stabilized output.