Staying Ahead of the Power Flow

Like most community-owned, not-for-profit utilities, CPS Energy's electricity distribution organization is driven by a singular mission: to provide its customers with reliable and affordable energy services. With disparate, legacy operational systems and supporting processes demanding greater investment and resources over time, the utility was further challenged by the growing consumption of the seventh-largest city in the United States.

In response, the utility undertook a comprehensive overhaul of its core legacy systems, replacing them with an integrated suite of operational systems. As a result, CPS Energy has improved operational efficiencies for control room and field resources, shortened outage times, improved customer communication during outages, and improved decision support and work management processes.

A Phased Approach

In 2003, CPS Energy performed a business case analysis on improving its electricity distribution design, operations and customer service. An important conclusion was the need to replace core legacy systems in the distribution business with an integrated suite of operational systems. The integrated suite would be leveraged for immediate productivity and customer service improvements, and also would serve as a platform for continuous operational improvements in the distribution organization.

The findings of the operations analysis became an actionable initiative by the mid-2000s when the utility engaged Ventyx, an ABB company, to deploy a distribution management system, Network Manager DMS, with a geographic information system (GIS) from ESRI. The effort also included integration to mobile communications supporting field crews, enterprise resource planning for customer service and work management, and network data conversion services.

In 2008, CPS Energy extended its power distribution operations by adding a supervisory control and data acquisition (SCADA) system, subsequently deploying into a fully integrated turnkey system incorporating SCADA, DMS and an outage management system (OMS) two years later. This phased approach has resulted in an integrated distribution operations platform that drives sustainable value throughout the organization.

By investing in an integrated technological platform to employ operational best practices, CPS Energy has reaped operational efficiencies for control room operators and field resources, shorter outage times, improved communications to customers during outages, improved decision support and collaboration, and more efficient system design and work management processes.

However, today's position in the utility's evolution toward a smarter grid did not come about in one swing. It began with one step.

The First Step

When CPS Energy first set strategies for its distribution organization, it was clear the utility needed to increase the efficiency by which facilities were designed and constructed. This included enabling planners and operators to test how proposed network additions would work with existing infrastructure and see how far a particular design has progressed (for example, which sections are energized and which sections have been built but not energized).

The utility also wanted to improve the efficiency with which it responded to customer interruptions and reduce average customer interruption duration. And finally, as a community-owned utility, CPS Energy wanted to provide its customer service representatives with access to more information, which would permit them to provide more specific and timely information to customers.

In 2006, these initiatives delivered the first vehicle for CPS Energy to achieve its operational modernization goals: a new OMS integrated with a GIS for the electricity distribution organization. The OMS was chosen based on its extensive capabilities, high integration quotient and integrated DMS advanced network applications for future phases.

With the integration between the GIS and DMS complete, planned components that had not yet been energized now could be included in the incremental update from the GIS. When new components are energized by field crews, control room operators can change the status of these new components to “in service” in the DMS. In this manner, CPS Energy personnel began using the GIS in planning and construction, providing operators with visibility of planned additions and enabling them to quickly update new component status in the DMS once they are energized.

The initial project also included integration of the DMS with enterprise resource planning (ERP). This step was necessary since CPS Energy customer service representatives use the SAP customer care system module when communicating with customers, such as when receiving outage calls.

For example, when an outage call is received in the customer care system, the integration pops up a Web call entry form with the customer's information prepopulated from the ERP. This allows the call to be documented in the DMS and also for customers to inquire about the status of their outage. Once the outage is restored in the DMS, customer callbacks are initiated by interactive voice-response technology. In addition, outage orders that require follow-up repair work are given an ERP work order number in the DMS and sent directly from the mobile workforce management system to the ERP plant maintenance module for servicing.

Closing the Operational Loop

The next step came in integrating SCADA into the distribution operations. The DMS was interfaced to control room OMS graphical displays and SCADA so CPS Energy distribution operators, who were already familiar with the OMS graphical user interface (GUI), could seamlessly use the same GUI when distribution SCADA was introduced.

The distribution SCADA module initially went live in December 2008. It communicates to controllers on distribution devices including circuit breakers, reclosers, switches, capacitors and voltage regulators. Communications to distribution substations is enabled through the use of dual-ported remote terminal units (RTUs). The distribution SCADA communication with field devices is facilitated by serial DNP3 and DNP/IP over unlicensed and licensed radios, as well as fiber optics.

In May 2010, CPS Energy went live with truly integrated OMS and SCADA in the DMS. The seamless integration between the OMS and SCADA modules today provides CPS Energy's power distribution organization with significant operational efficiencies:

Increased operator efficiency with one system, eliminating the need to go to multiple systems with potentially different data
Integrated operator GUI, including the ability for operators to control SCADA devices from the OMS maps or SCADA
Streamlined login (single sign-on with SCADA sign-on initializing the OMS tabular displays and maps)
Simplified authority management of areas of responsibility within one system
Integrated security analysis for substation and circuit operations to check for tags in one area, affecting operations in the other
Consolidated system support for DMS/OMS and distribution SCADA
Simplified data engineering through coordination of SCADA point and GIS data changes, using the integrated graphical data engineering environment
Multiple inter-control center communications protocol links from the OMS module to accommodate communications with different legacy SCADA systems.

CPS Energy also has upgraded the interface between the GIS and DMS with a future vision to build and maintain substation one-line diagrams within the GIS environment and import them into the DMS using the same method of incremental update as that used for the existing parts of the network. The utility expects this efficiency will eliminate the need to maintain parallel substation one-line diagrams in the SCADA system, except for certain special cases.

Driving Future Optimization

As it continues to manage demand growth, CPS Energy is keeping an eye on the changing energy landscape and emerging technologies. The utility currently plans to leverage its operational investments as it continues to enhance automation and integration capabilities with advanced DMS network applications:

Unbalanced load flow analysis
Fault location
Automatic restoration switching analysis (self-healing)
Volt/VAR optimization.

Advanced DMS network applications will provide distribution operators with improved visibility across the system, the ability to reduce average customer interruption duration, the ability to operate the system with an improved knowledge of equipment capacity margins, and improved control over voltage and VAR flow on the system. The OMS and advanced DMS network applications use a single, dynamic distribution network model, saving CPS Energy IT staff from having to maintain and synchronize two separate models. The master network model will be kept in the GIS, with a single incremental update process between the GIS and DMS.

In addition, CPS Energy is exploring the role advanced metering infrastructure (AMI) might play in its distribution operations. This includes understanding possible applications of integration between the AMI/meter data management systems and DMS, and the use of the AMI communications infrastructure for distribution automation.

Benefits Realized

Since 2004, CPS Energy's foresight and investment in a sustainable enterprise operations platform has enabled its power distribution organization to sustainably and continuously improve efficiency, electricity reliability and service to its customers. They have achieved many of the goals set for these investments:

Improved operational efficiencies for control room operators and field resources, particularly during outage events
Shorter outage times and improved communications from customer service representatives to customers during outages
Enhanced awareness of distribution loading and voltage profiles, along with an ability to initiate SCADA control from the OMS GUI
Improved decision support and collaboration among CPS Energy personnel
More efficient system design and work management processes
A platform for continued enhancements to distribution automation improvements.

Tommy Ross ([email protected]) is a professional engineer in the state of Texas with 10 years of experience in outage management systems and distribution SCADA. He is presently manager, OMS/DMS SCADA support at CPS Energy in San Antonio, Texas, and holds a BSEE degree from The University of Texas at San Antonio.