High-voltage generation reserves cost more than would portable, small-scale units to keep critical services on line during a major power outage.
Why Outage Management Must Change
Smart grid advancements call for a new approach to restoration.
In the not-too-distant past, utility distribution networks were managed by two non-competing technologies: outage management systems (OMS) and distribution SCADA (supervisory control and data acquisition). Today, this model is changing rapidly. Smart grid advancements have brought new combinations of advanced technologies, often working together in a real-time operation or a real-time network. In the smart grid, the technologies that are applied must work together dynamically; by their very nature, they must adapt to changes in the grid in a coordinated fashion. Changes to the network brought about as a result of one technology or system usually will have an effect on another system, but there remains only one real-time network state at any given time.
For example, two common smart grid automation technologies, feeder self-healing and power optimization, must be able to interact effectively. Many smart grid solutions with power quality improvement as their business objective are applying technologies such as loss minimization (LM), which performs capacitor switching to reduce losses. In other cases, conservation voltage reduction (CVR) is applied by reducing voltage through coordinated switching of regulators and load-tap-changing transformers. The coordinated combination of each for integrated volt-VAR control (IVVC) provides additional benefit.
These applications can't assume to know the real-time network connectivity status of the devices they're controlling. Operation of self-healing systems can result in the switching of regulators and capacitors from one feeder to another, so related smart grid systems must be able to adapt to these network changes. The problem becomes more pronounced as distributed generation or distributed energy resources are applied to the feeder operation, since this will affect the voltage profile for the downstream feeder. Likewise, these smart grid applications all must adapt their operations in a coordinated fashion. For optimum efficiency and safety, they must operate from a common topology model where all applications maintain awareness of the real-time network state, and they in turn must use the real-time state in their respective solutions.
The traditional OMS now must operate in this new dynamic distribution network environment. In a way, the OMS competes with other operational systems for information, overlapping functionality, visualization, and maintaining the network topology.
Integrated Real-Time System
Many utilities build a smart grid infrastructure without considering the cost to maintain it. The largest single cost, accumulated daily over the life of the system, can be data maintenance. This maintenance includes the database itself, the detailed graphical map display and the network model.
The utility executive must ensure that the smart grid applications use a unified network model unencumbered by the traditional segmentation of data into operational silos. For example, existing network connectivity models previously were maintained only in the GIS (geospatial information system). As a result, many OMS vendors and utilities built a system tightly coupled with the GIS model. In this case, customer operational data, such as trouble calls, is sent to the OMS. Data from