|

Achieving Power System Balance

Power System Balance

March 8, 2023

A small utility in Tennessee installed a complete automated power factor balancing system without complex SCADA

For the power generation industry, maintaining power system balance as closely as possible to the ideal power factor (PF) of 1.000 using correction capacitors and other technology is critical. Power factor is a measure of how effectively electricity is used, with an equal 1.000 PF benefiting both the customer and utility, and a low or high PF indicating poor electrical power utilization. A low power factor can overload generation units making them work harder for the same amount of power. A high power factor can cause instability to equipment on the distribution network as the voltage rises beyond normal capabilities. In contrast, improving the PF can maximize current-carrying capacity, improve voltage to equipment, reduce power losses, and lower electric bills.

“The challenge for small municipal utilities and co-ops required to maintain proper power system balance is that they are more susceptible to large industrial loads and typically do not have complex SCADA systems to automate the process”, says Ryan McAuliffe, Sales Engineer, NovaTech Automation, a substation automation company that has served the power transmission and distribution market for over 30 years. In addition, smaller utilities may not have enough operators to manually monitor and effectively control the PF on a 24/7 basis.

Fortunately, cost-effective, self-contained, automation platforms can utilize programming logic schemes to maintain power system balance, minimizing the need for manual oversight and control.

“Today, automation platforms can maintain system balance with PF at virtually 1.000 with accuracy to 3 decimal places. The control system calculates whether the power system is out of tolerance, and if so, initiates a correction using the capacitor banks to keep the power factor at 1.000,” says McAuliffe.

Automating System Balance

In a recent example, a small municipal power utility in Smithville, Tennessee required an automatic capacitor control logic scheme for their distribution network.

“The municipal utility has a small distribution network and is contracted [with a major Transmission Network Operator], under penalty of fine, to keep the PF of the power system as close to 1.000 as possible. However, the system includes a rather large industrial customer, so the utility needed a better way to manage their PF,” says McAuliffe.

The utility has two substations with interconnecting feeders through their distribution network with the feeder circuit breaker on either end acting as the open or closed point. The capacitors are positioned outside the substation fence at various locations on those interconnected feeders.

As a solution, the utility chose to implement a complete integrated power balancing system including capacitors, a capacitor bank controller, circuit breakers, and a controlling RTU.

Operators can zoom into animated emulations of individual Cap bank controllers and force controls.

All monitoring, control, visualization, and security of the integrated utility power balancing system is provided by the OrionLX Substation Automation Platform by NovaTech. The OrionLX is a communication and automation processor that can be integrated with practically any equipment, usually microprocessor-based relays, meters, and other IEDs as well. It can connect to SCADA system or itself be a basic SCADA system.

The Orion Tile Annunciator is used to alert operators of alarm conditions.

The system uses open-source web technologies and pre-configured template pages. This simplifies the building of interactive SCADA and local HMI screens to view data from connected IEDs and 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.

“With the substation automation platform, the utility did not need a dispatcher for PF balancing, only a supervisor to oversee the facility,” says McAuliffe.

According to McAuliffe, the platform’s System Balance scheme helps to ensure that each substation maintains a 1.000 power factor. The scheme will initialize values and then load all previous retentive values or default values if there are no retentive values. With the scheme, an overall leading power system state will turn off one or more capacitors, and an overall lagging power system state will turn on one or more capacitors, providing alerts and control.

To ensure that individual feeders are in balance and within tolerance, a second logic scheme has been proposed for Individual Feeder Balance that will run every five minutes after completion of the primary scheme. This is needed due to the configuration of the utility’s distribution network assets. Although total substation power factor can be balanced, it is possible to have two feeders out of balance in the condition of one lagging and one leading. The second scheme looks at individual feeder power factor tolerance and makes corrections as needed.

Together, the primary and secondary balancing schemes provide integrated Volt-VAR regulation and optimization. The schemes automatically switch capacitor banks in and out to maintain power factor very close to balance, summing PF on each feeder and comparing it with the metered value reported to the power provider. The automation includes features to reduce wear and maintenance such as never switching the same capacitor bank twice in a row.

Capacitor bank status screen

The system maintains the ability to manually control all capacitor banks and provides web-based HMI for monitoring and control of breakers and IEDs in substations.

“Automated power system balancing comes in handy for smaller utilities because they don’t need to monitor as closely. With installation comes more automatic control that can be scaled up to the number of required substations,” says McAuliffe.

Overall, the primary and secondary balancing schemes have been extremely beneficial for the small municipal utility in Tennessee. The schemes have reduced the labor required for the utility to look after the distribution grid, and it has maintained almost full power factor compliance with the Transmission Network Operator.

Important_Links_Bar.jpg

More Information

Related Articles

Network Infrastructure Featured Product Spotlight

PBUS 14 Panduit logo 400

This webinar presented by Beth Lessard and Keith Cordero will be highlighting three Panduit solutions that will optimize network equipment and cabling to ensure that your spaces are efficiently and properly managed to support ever-evolving business needs of today and beyond. Products that will be featured include PanZone TrueEdge Wall Mount Enclsoure, Cable Managers, and Adjustable Depth 4-Post Rack.

REGISTER HERE


Editor’s Pick: Featured Product News

Siemens: SIMOVAC Non-Arc-Resistant and SIMOVAC-AR Arc-Resistant Motor Controllers

The Siemens SIMOVAC medium-voltage non-arc-resistant and SIMOVAC-AR arc-resistant controllers have a modular design incorporating up to two 12SVC400 (400 A) controllers, housed in a freestanding sheet steel enclosure. Each controller is UL 347 class E2, equipped with three current-limiting fuses, a non-load-break isolating switch, and a fixed-mounted vacuum contactor (plug-in type optional for 12SVC400). The enclosure is designed for front access, allowing the equipment to be located with the rear of the equipment close to a non-combustible wall.

Read More


Sponsored Content
Electrify Your Enterprise

Power is vital to production, and well-designed control cabinets are key. Allied Electronics & Automation offers a comprehensive collection of control cabinet solutions including PLCs, HMIs, contactors, miniature circuit breakers, terminal block connectors, DIN-rail power supplies, pushbutton switches, motor starters, overloads, power relays, industrial Ethernet switches and AC drives engineered to keep your operations running safely, reliably and efficiently.

Learn more HERE.


Products for Panel Builders

  • Celduc: New SMQR Quad Series Solid State Relay

    Celduc: New SMQR Quad Series Solid State Relay

    Celduc’s Solid State Relays are designed for industrial applications where fast and long electrical life in switching is required. Celduc has recently launched a new range of Quad AC Output Solid State Relay. With this new SMQR Series you will get four independently controlled AC output Solid State Relays in an industry standard package. With the models… Read More…

  • Brady: M211 Portable Bluetooth Label Printer

    Brady: M211 Portable Bluetooth Label Printer

    Design. Preview. Print. All from your phone. The M211 portable Bluetooth label printer is a tough, compact labeler that belongs on any jobsite. Seamlessly design, preview and print labels right from Brady’s Express Labels Mobile app for iOS and Android. Create custom labels from your phone’s familiar keyboard via ultra strong BLE Bluetooth technology. Maximize… Read More…