Lineman's and Cableman's Handbook, Eleventh Edition
Filled with over 1500 illustrations, this classic text explains the basic principles, equipment, standards, and safety regulations required for optimal on-the-job performance.
TABLE OF CONTENTS Lineman's and Cableman's Handbook, Eleventh Edition
Chapter 9: Distribution Automation
Electric systems are becoming more remotely monitored controlled, and automated to improve reliability and power flow. Vendors are introducing communication equipment that retrofits existing isolation devices to control the isolating equipment. The new equipment allows the Control Room personnel (described in Chap. 2) to utilize the supervisory controlled and data acquisition (SCADA) system to not only monitor the system but also to perform remote site switching or isolating if needed. Personal computers and personal computer software applications have aided the advancement of distribution automation. A communication system must be in place to transmit the signals via the SCADA system to the equipment.
MONITORING
Past and present distribution automation projects are aimed toward system monitoring. Monitors are placed on the distribution system to sense momentary and continuing power outages, under and over voltages, and excessive fault currents. In some instances the status device provides feedback to the SCADA system. The majority of devices simply log or display status and must be field verified to obtain system information.
Circuit fault indicators shown in Fig. 9.1 may be installed in either overhead or underground applications. An example of an overhead application is the utilization of the device just beyond a three-phase recloser positioned as shown in Fig. 9.2. In the event of a single-phase line-to-ground fault, the recloser (reclosers are referenced in Chap. 18) will lock out after progressing through the desired sequence of trips and recloses. The indicator will sense fault current and remain in the faulted position. It is important to...
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