Products

GOLD for ServRestor
A Global Optimal- Linked Computer Package for Distribution
Networks Service Restoration
Version 2

As distribution systems continue to grow in size and complexity, the amount of time required to restore power to customers in the aftermath of a fault reaches a level, which produces unacceptable economic and social costs for an industrialized society. Currently, the restoration is performed step-by-step and mostly manually, based on pre-established guidelines and operating procedures.

Fast Service Restoration Benefits

Fast Service restoration (via network reconfiguration) has multi-fold benefits:

• First, it reduces the inconvenience and the cost of the outrage to the customers.
• Second, it enables the utility to resume earning revenue for energy sales.
• Third, the number of customer complaints is reduced.
• Fourth, it considerably reduces the undiversified component of cold load pickup.
• Fifth, it can greatly improve several important distribution system reliability indices.
• Sixth, it enables the utility to provide enhanced service to critical customers who have contracts with the utility for reliable power delivery.

To realize the above multi-fold benefits, BSI has developed a practical computer package, under multi-year sponsorship of power industry users, for fast service restoration. The package has been intensively evaluated on practical distribution systems with promising results. This package is currently being used by several industry users.

Comprehensive Modeling Capability

In order to take the physical realities of distribution networks into account, the package has comprehensive modeling capability for different components including:

• Primary power networks
• Three-phase transformers with off-nominal tap ratios as well as core and copper losses
• The different winding connections of three-phase transformers such as grounded wye-grounded wye connections, grounded wye-delta connections, etc.
• Cogenerators
• Nonlinear load models
• Voltage sensitive load models for single-phase, two-phase and three-phase loads
• Shunt capacitors
• Reactors

Service Restorations

The service restoration problem is a multi-objective, multi-stage, combinatorial, nonlinear, constrained optimization problem. The main disadvantage of the previously proposed algorithms are that many do not address the fact that a solution restoring all the out-of-service loads may not exist. Hence, alternate plans to restore only part of the out-of-service loads are not discussed. Also, the existence of priority customers such as hospitals and fire stations is not considered by most of the existing algorithms. These oversights lead to an unsatisfactory approach to the service restoration problem. In addition, most of the existing solution algorithms may be too slow to be used for on-line applications.

Features of the Package

BSI has developed a computer package written in C++ with a graphical user interface (GUI) for service restoration on the PC. The main features include:

• It meets priority customers in the sense that if the entire outage load cannot be serviced, then priority customers are serviced and a minimal amount of load is dropped
• It can handle multiple fault locations
• It is applicable to large-scale unbalanced distribution networks
• It incorporates network flow programming techniques to quickly identify candidate switch operations