Public Utilities Reports

PUR Guide 2012 Fully Updated Version

Available NOW!
PUR Guide

This comprehensive self-study certification course is designed to teach the novice or pro everything they need to understand and succeed in every phase of the public utilities business.

Order Now

Standby Generation: A New Proposition

A cost/benefit analysis of full interconnection of customer-owned standby generators.
Fortnightly Magazine - June 1 2002

the utility source.

With a closed transition transfer system, the second interruption is avoided. When utility service is restored, the backup generator with a closed transition transfer system control operates in parallel with the utility, and the load can be seamlessly transferred. In scenarios with a backup generator operating prior to the utility service disruption, the consumer does not experience any disruptions in power supply.

The economics of power disruption vary with individual consumer scenarios. Typically, industries with continuous manufacturing processes or with intensive data processing functions cannot tolerate even a momentary service outage. In these industries, a closed transition transfer system is crucial. In advanced applications, energy managers monitor weather forecasts for extreme conditions. When weather conditions are likely to cause an outage, the backup generator is placed in test mode and load is transferred seamlessly from the utility. When the storm passes, the load is seamlessly transferred back to the utility, and then the generator is shut down. In the future, third-party services such as commercial weather forecasters, utilities, generator retailers, and technology firms may provide automatic dispatch services alleviating energy managers the responsibility of monitoring meteorological conditions.

For consumers with power factor issues, a generator with a closed transition transfer system can improve power quality. Power quality problems can be defined as the difference between the quality of power delivered and the quality of power required for a specific load. Power quality issues are resolved in three ways: reducing the variations in the power supply, improving the load equipment tolerances, or conditioning the power before it reaches the load. This article addresses the ability of a closed transition transfer system to reduce the variations of the power supply.

Utilizing a backup generator to address power quality issues can provide a long-term solution. Local conditions should be analyzed to confirm this approach. Installing power-metering equipment that continuously monitors the power system over time can supply the data necessary to objectively assess the cost-effectiveness of a closed transition transfer system. The connected load can affect power quality at a customer's site. Customer-owned loads, such as motors, could cause the power factor to vary below many utilities' prescribed standards. This in turn creates an additional charge on the customer's monthly energy bill since the utility must correct this problem at the utility owned distribution site. To avoid these charges, the customer's connected load power factor can be stabilized when a customer-owned generator synchronously operates with the grid. 1 With a closed transition transfer system, the generator set can help correct or offset excessive inductive loads that cause lagging power factors. An isolated open transition transfer system cannot assist in correcting power factor issues unless a dedicated generator serves the problem-causing load.

Flexibility for Testing, Enhanced Peak Shaving and Load Following

In many critical applications, backup generators are tested under load to simulate performance in an actual emergency. An open transition transfer system requires facility operations be suspended while power is transferred from the utility to the backup generator or that the generator is tested without load-a practice harmful to the generator that