Transmission Line - Reliability Tab

This tab appears when your EasyPower license includes the optional Reliability feature and the component is included in reliability analysis. Use this tab to track reliability data on your system components. The reliability features are based on IEEE Standard 493-2007. Refer to the standard for additional information.

Note: Rectifiers, inverters, and AFDs are treated as single nodes (branches) and their reliability data applies directly to them. These can become dependent first-order cut sets if connected to first-order buses.

Figure 1: Reliability Tab

Option Descriptions
Option Description

Import

Click Import to import reliability data from the selected library, class, and category into the reliability data fields. After you import, the imported values appear below the Import button.

  • Library: The reliability data library. We provide Annex Q data, but you can select your own library if one is available. Use the library to import reliability data.
  • Category: The category for the component in the library data. For example, the category for a bus could be a control panel or a switchgear. The category determines which classes are available.
  • Class: The class for the component in the library data. This is used to provide more exact reliability data based on the particular characteristics of the component.

Note: You can also import reliability data for all components in the one-line at the same time. See Importing Reliability Data for more information.

Failure Rate

The calculated rate of failure for the component on a yearly basis. If you have imported library data, the imported value is displayed here. You can manually type a value to have the program use that value instead.

Note: For cables, transmission lines, and busway, this value is per unit of length.

Repair Time

The mean average time to repair the component, expressed in hours. If you have imported library data, the imported value is displayed here. You can manually type a value to have the program use that value instead.

Note: For cables, transmission lines, and busway, this value is per unit of length.

Replace Time

The mean average time to replace the component, expressed in hours. If you have imported library data, the imported value is displayed here. You can manually type a value to have the program use that value instead.

Note: For cables, transmission lines, and busway, this value is per unit of length.

Repair Cost

The estimated cost to repair the component. This value is not used if the Action upon failure is set to Replace.

Replace Cost

The estimated cost to replace the component. This value is not used if the Action upon failure is set to Repair.

Action upon failure

The recommended action to take upon failure of the component: repair or replace.

Downtime Costs

The downtime cost for the individual piece of equipment. This is available for a bus, MCC, panel, motor, or load.

SC Failure Mode (%)

This is an adjustable percentage that is applied to the failure rate of indirect protective devices and represents the percentage of total failures in each failure mode. For circuit breakers, the default is 9%. For switches, the default is 0% (no reliability).

Install Date

This option is reserved for future use.

Reliability Data for Cables, Busways, and Transmission Lines

Lines such as cables, busways, and transmission lines have some additional fields that relate to their connections. Each line has two connections: one on the line side and one on the load side. The connection reliability metrics are per connection.

If the unit is specified as Per Unit on the Specifications 1 tab, the per unit length that the reliability is based on appears here.

Figure 2: Cable Connection Reliability Data

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