By Guerry Waters, Oracle Utilities
In North America, electric utilities have long managed their distribution networks using various applications with distinctly different spheres of responsibility. Outage management, for instance, has been the go-to application for accelerating repairs in the wake of accidents or storms. Supervisory control and data acquisition (SCADA) manages the ongoing operations of transmission and subtransmission lines and equipment between the generator and distribution substation. And, distribution management oversees the safe and secure operation of the electric facilities for equipment and lines between the substation and the meter. It also provides the visualization and decision support environment for efficient and effective use of electric assets.
These functions typically reside in separate applications for reasons that are almost entirely historic. As in most businesses and industries, utility automation has computerized business processes incrementally. The result is multiple applications that address different issues, spread across the distribution network.
There is a positive aspect to having multiple applications. They allow utilities to simplify purchasing and training, ease testing, and allow incremental improvements. In addition, their implementation has affected only a segment of network service, permitting human operators and other applications to fill gaps with temporary responsibilities and work-arounds.
There are, however, serious negatives to application separation. Each new piece of software comes with increasing levels of costly and complex system and application integration. Even more detrimental, separate application operations have not furnished a truly global view of the network. Multiple network applications have done a good job of supporting decision-making, but they have not provided a full grasp of the big picture.
Today, managers increasingly question the need to retain application separation. Fewer, broader applications, they reason, might offer opportunities to increase efficiency. Business processes might cover more of the functional requirements before handing off data to a system of record. Reports run against a more cohesive and broader base of network information might reveal gaps or redundancies not obvious with a narrower view. And fewer application integrations to build and maintain would significantly reduce associated support and maintenance costs.
In light of the move toward the smart grid, a near-term merger of network-oriented applications appears as all but imperative. Adding smart grid functions and complexities by adding new applications, one on top of another, would threaten to result in administrative chaos and cost nightmares. Fortunately, the future of combined network applications is already taking place. One example is the gradual but clear merger of outage management and distribution management.
Outage and Distribution Management Come of Age
Outage management is of relatively recent vintage as a network application. For utilities with large geographic territories in storm-prone regions, outage management has established its credentials as a vital link between repair crews and central dispatch offices. By routing field personnel directly to the site of a damaged or inoperable line and by tracking and directing repairs—frequently at multiple sites simultaneously—outage management has dramatically shortened the time between outage report and service restoration. It has helped utilities meet and exceed customers’ and regulators’ expectations for service reliability.
Outage management is not universally deployed, however. Small utilities have found it less expensive to hire or borrow more workers for repair crews than to use computer applications to accelerate repairs. Municipal utilities with their dense populations have far less difficulty in locating outages than do, for instance, cooperatives stretching across multiple rural counties. Distinct from outage management lies distribution management—the decision support and automation of the feeders that connect substations to meters. It substantially improves the safety and security of operations such as switching, as well as the utility’s ability to perform controls on facilities. The automation also yields improvements in system reliability, thus increasing the justification for implementation.
As with outage management, use of distribution management is not universal. Many utilities substitute a combination of historical feeder-load spreadsheets, personal knowledge of the electric distribution network, and radio-dispatched operations in the field. As utilities grow and as knowledgeable individuals retire, however, these substitutions become less and less sustainable.
A Smart Grid Mandates Outage and Distribution Management
In the past, utilities could avoid using outage and distribution management applications. That era, however, is passing, for a number of reasons:
- The disappearance of grid over-capacity. In the past, overbuilding permitted customers to enjoy reliability even though grid operations were less than efficient. Today, however, excess grid capacity is largely a thing of the past. Efficiency achieved via distribution management is at least a partial substitute.
- Capital constraints. News outlets are full of stories about cost-constrained communities facing aging infrastructure. Cities and counties are outgrowing their electrical systems while simultaneously needing to repair or replace water and gas mains. For most, recession and falling housing prices have depressed the tax base. The resulting pressure to carefully limit and prioritize infrastructure replacement places a premium on applications that can move more electricity more reliably over the existing grid.
- The national focus on grid efficiency. Federal bills calling for smarter grids and advanced metering aim for the reduction of both generation emissions and energy costs, while simultaneously preserving wilderness and local property values. Expanding distribution networks becomes politically untenable when there is a clear software alternative.
- The growth in per capita and industrial electricity use. This magnifies the negative effects of any outage and increases the urgency to accelerate restoration. This driver is particularly strong for those who foresee an increase in major storms as a result of global warming.
- Customer involvement. Constantly increasing demand is a problem too large for utilities to address alone. Most analysts and regulators see customers as an essential part of the solution. Giving them the tools to do their share, however, involves grid improvements available only with applications such as outage and distribution management.
Today, utilities considering increased network computerization as a response to these challenges have a distinct advantage over utilities in the past. It is no longer necessary to consider outage management separately from distribution management. In fact, it is essential that these two applications coexist in a symbiotic relationship, coupled far more closely than they can be with mere point-to-point integration. Only when outage and distribution management unite can they seamlessly address the complete life cycles of network business processes. Let’s consider some examples.
Root Cause Analysis
Outages arise from different causes. And while differentiating those causes is not a top priority for the field service technician making a 2 a.m. repair, identifying the cause can make a significant difference to ongoing operations. Are animals causing faults in a particular area? Is pole placement at intersections leading to accidents? Is demand on a feeder regularly exceeding its planned capacity?
Outage management can capture all the relevant data for these situations. Even more important, it can also analyze root causes. Utilities maximize the value of these analyses when they can use them to alter not merely outage management procedures but also distribution management procedures and the interaction of the two applications.
Electricity networks operate far more efficiently when they use automated, closed-loop processes. Grids can minimize feeder losses and distribute power more efficiently, for instance, when unbalanced three-phase power flow regulates the power transformer tap positions and cap banks, thus avoiding Volt/Var violations.
Predictions Using Meter Data
A combined outage/distribution management system can use advanced metering data to provide historical load information into the power flow. This enables a more accurate forecast of peak load conditions. As a result, the system can provide violation constraint alarms that warn an operator of the need to take actions to mitigate predicted problems. The number of crises plummets.
Predicting outage location has in the past been the purview primarily of the outage management system. But as the deployment of smart grid sensors increases, so does the distribution management system’s ability to sense trips (faults) in switches that are monitored and controlled by a SCADA (e.g., feeder circuit breakers (CB) and downstream automatic circuit reclosers (ACR)). The most accurate crew deployments in these instances result when outage and distribution management join forces—that is, when outage management predicts probable outage locations and distribution management identifies the faulted feeder section(s).
Additionally, when distribution management expands to include a fault isolation and recovery system, distribution management can immediately—though temporarily—restore power to some or all customers. It can:
- Identify the faulted section using telemetered protection trip and fault indication (FI) flags.
- Isolate the fault.
- Restore power to some customers by automatically switching them to nonfaulted sections of the line.
This distribution management function cannot actually fix faults or equipment failures. However, its combination with outage management functions locates outages more accurately, dispatches crews more effectively, and ensures that utilities can work around damages in a planned and coordinated fashion.
The Challenge of Advanced Metering
For many utilities today, interoperable or combined outage and distribution management applications can make some modest difference in operational efficiency. The full realization of advanced metering, however, will change outage/distribution interoperability from desirable to imperative.
Advanced metering promises to provide hundreds of thousands of daily data points unavailable today. Smart meters—now being deployed in states from Pennsylvania to California—will communicate not merely interval meter reads but also information on power quality and blink-outs.
These data have uses far beyond mere billing. When analyzed in a combined outage and distribution management context, they can help:
- Correctly size transformers and other distribution equipment, reducing the need for expanded grids.
- Determine where and how often to perform preventive maintenance.
- Provide an intricate view of usage that enables grid operators to better manage nondispatchable resources.
- Anticipate power flows resulting from changing demand response and critical peak pricing programs.
- Initiate focused demand response activities based on detection of developing overload conditions on various segments of the distribution network.
- Provide a basis for new competitive services such as power quality guarantees.
The combined data from outage and distribution management give system operators a more comprehensive view to network observability and predictive analysis. Operators can thus move away from merely reacting to alarms and dispatching jobs and toward a cohesive vision of temporal response: immediate issues and priorities, near-term plans, and future actions.
There are clear, measurable results. Crew dispatching for restoration improves. Outage times shorten. Utilities can more quickly detect and mitigate overloads.
In short, bringing outage and distribution management together—ideally into a single application—enhances grid operation to the benefit of both utilities and customers. It is a combination that helps ensure that the smart grid moves from concept to reality.
Guerry Waters is vice president, industry strategy at Oracle Utilities.