Automation Overhaul Benefits Smaller Utilities

Summary

Traditionally, small municipal electrical utilities like the one in Seguin, Texas, have believed that implementing a supervisory control and data acquisition (SCADA) system was out of reach due to the perceived high initial costs, high licensing fees, and complexity.

However, advances in web-based SCADA systems have transformed the process of installing, configuring, and managing these systems to control substation performance. Modern web-based systems streamline installation and maintenance and provide engineers with a modern user interface they can easily configure—a factor that now allows even smaller cities to operate like large investor-owned utilities with hundreds of substations

SCADA integration plan

Consider the scenario in Seguin, Texas. The utility embarked on an ambitious plan to integrate a new SCADA system with Outage Management System software, citywide Wi-Fi, advanced metering infrastructure (AMI) technology, GIS mapping, and energy efficiency software to improve customer reliability and education. The system was designed to enable utility engineering teams to manage a dispersed network and more efficiently support the cooperative’s mission for reliable, cost-effective service.

The Seguin had no trouble justifying the SCADA investment, even though there are only three substations. The system provides the same degree of monitoring and control system as implemented by larger utilities. Seguin has a population of 25,090. Approximately 8,200 residential customers, as well as several large industrial facilities, rely on power from the electrical system. The utility operates three substations with 14 circuits, which requires 19 employees to manage 110 miles of overhead and 26 miles of underground electric lines.

To complete this ambitious SCADA implementation, the city turned to M&S Engineering, a full-service electrical, civil, and subsurface utility engineering and surveying firm, to develop all the specifications outlined in the initial bid.

Solutions for Seguin

For the physical infrastructure and sensors, M&S Engineering specified an AMI system from Aclara that includes nine collectors that gather smart meter readings. AMI systems enable electric utilities to collect and harness the power of smart meters, edge devices, and data to meet challenges such as substation monitoring, load monitoring, load control/demand response, fault detection/ outage management, distributed generation, conservation voltage reduction, and customer engagement. The data is then transmitted over a newly installed, citywide Strix Wi-Fi system to a central network, which allows multiple users and departments to access the information.

To enhance communication and decision-making, assets such as electric poles and meters are now mapped and coordinated through ESRI, a geographic information system (GIS) mapping company. The GPS coordinates facilitate more efficient dispatching of utility trucks and service crews when needed. For the SCADA system, M&S Engineering selected the OrionLX system, a communication and automation processor, from the Power Division of NovaTech Automation (Lenexa, Kan.), a substation automation company that has served the power transmission and distribution market for more than 30 years.

The communication and automation processor can connect to nearly any substation device in its native protocol, perform advanced math and logic, and securely present the source or calculated data to any number of clients in their own protocol. The system can be integrated with practically any equipment, usually microprocessor-based relays, meters, and other intelligent electronic devices, as well. It is then connected to the SCADA system.

The system uses open-source web technologies and preconfigured template pages, which simplifies the building of interactive SCADA and local human-machine interface (HMI) screens to view data from connected intelligent electronic devices and remote terminal units (RTUs) using standard web browsers. Engineers can open multiple browsers to have graphical interfaces for the different substations and key remote monitoring features on different tabs, which eases network monitoring. Multiple users can be logged in simultaneously.

For the most economical setup, Seguin opted to install a communication and automation processor in each of its three substations that connect wirelessly to a browsing PC with multiple monitors, each representing a substation. Another configuration option for smaller utilities is a centralized model, in which a communication and automation processor is installed in the central office (taking the place of the browsing PC) that accesses each substation communication and automation processor, then serves up the information to connected networks.

The communication and automation processor RTU (figure 1) has improved in the integration of functions previously accomplished by separate physical devices. For example, separate alarm annunciators and PCs do not have to be connected to the RTU—only a monitor, keyboard, and mouse need to be connected. The communication and automation processor tile annunciator is a preengineered product that can be set up in minutes to provide alarm status. When combined with sequence of events recording, relay event retrieval, intelligent electronic device faceplates, one-line diagrams, control screens, and trending, the communication and automation processor can serve as a complete substation HMI or an economical small SCADA system.

Minimizing dispatches

After the SCADA system, microprocessor-based relays, and other components were installed, the city could respond to issues more quickly, resulting in shorter outage times for customers. Previously, personnel would have to drive out to a substation when there was an issue with a feeder or transformer. Now, most issues are diagnosed remotely.

“Now, the monitoring is done from the office. The engineering team remotely logs into the substation devices to view the data, settings, sequence of events, and make changes if needed. They usually do not have to visit the substations in person, so the labor involved in monthly checks is significantly reduced,” said Wright.

“With SCADA, they can monitor and capture events such as low voltage or high voltage at the bus, which helps when troubleshooting customer complaints and enables remote manual control of voltage regulators,” added Wright. SCADA also allows the city to monitor the power factor on individual circuits and then to switch capacitors in or out, without having to depend on other companies.

The city of Seguin plans additional system upgrades, including an energy efficiency program featuring a new VoIP phone system and approximately eight additional Wi-Fi units and accompanying antennas to improve “self-healing” properties. The utility is also investigating automated switching, which would involve adding control panels and motors to the existing air break switches to facilitate operations through the SCADA system.

_{This feature originally appeared in InTech Focus: Control Systems 2022, the InTech Focus ebook for September 2022.}