What are the effects of and to power quality from alternative power sources?
The increased reliance on alternative power sources — both as backup in the event of an emergency and as a primary power source — exposes a number of vulnerabilities between power quality and alternative power systems and their components. Alternative power sources typically are used to change voltage levels and frequency, isolate critical equipment, provide voltage regulation, and maintain power to a load during utility power interruptions. They can cause several types of disturbance. Peak currents or harmonic currents generated by the load can interact with the impedance of the alternative power source, causing voltage instability and distortion. Off-line UPS de4signs may pass common mode disturbances through to the protected load. On-line UPS designs may have bypass circuitry which allows the pass through of common-mode disturbances to the protected load. And SCR-controlled battery chargers may add impulses back into the incoming power line. Conversely, power disturbances can affect
