Selecting the proper voltage sag mitigation option for high-current equipment can be tricky. Most of the mitigation technologies available today are designed for lower current applications (e.g., control circuits). In most power quality cases, the control systems are the most sensitive to voltage sags in the electrical system. However, manufacturer's warranties can be void by installing control mitigation technologies. What can be installed when the entire piece of equipment needs to be mitigated, especially in high-current applications?
When high current or entire equipment mitigation is required, a dynamic sag corrector (DySC) can be used to solve the problem. The DySC is comprised of power electronics that monitor and correct voltage sags for both single- and 3-phase applications. The offline design provides a highly efficient topography — 96% to 99% efficient, in most cases. The load range is generous as well, offering 2A to 2,400A. The technology operates by magnifying the line voltage remaining during a sag event, even to 0V. This is accomplished without the use of batteries, lowering the cost of operation over the life cycle of the equipment.
A DySC is best applied when an entire machine or production line needs to be mitigated. It can carry motor load and variable frequency drive loads providing up to 5 sec of ride-through. The recovery time is a maximum of 5 min. between operations. The output voltage during the sag event is matched to the pre-sag input voltage with a near-perfect sine wave.
DySCs are excellent solutions for semiconductor fabrication equipment, robotic manufacturing equipment, and critical equipment where other options may void the warranty. Many companies know the value DySCs can provide in saving costly shutdowns and build them into the construction of new installations. If an installation needs to be modified, DySCs are compact and easy to install on the input to the equipment.
Being well-versed in the many different mitigation options available on the market will help you quickly solve power quality problems either in the design phase or after construction is complete.
