Distribution Protection and Restoration Systems: Design Verification by Reliability Indices

In designing a protective scheme and circuit configuration for distribution circuits, it is desirable to quantitatively compare the performance of distribution circuits for various alternatives. The indices used for such comparison must be sensitive to the number, type, and location of protective devices, to circuit exposure, and to restoration practices. Four reliability indices are defined in this paper. An analysis technique is presented which evaluates the four reliability indices for any given distribution feeder in a logical and consistent manner. A digital computer program employing the above analysis techniques is applied to a sample problem which demonstrates the effectiveness of various protective devices and operating practices in terms of the reliability indices.