Instrumentation & Controls, O&M

Time to Replace Your Hydro Control System? Go With a Modern DCS

Issue 4 and Volume 122.

Combine centralized control with industrial IoT data to optimize your plant’s performance

Many hydroelectric plants today use outdated control and electrical systems. As a result, these plants experience a greater risk of operational stoppages and downtime. A modern DCS system can mitigate these risks. Photo courtesy: Rockwell Automation

Many hydroelectric plants today use outdated control and electrical systems. As a result, these plants experience a greater risk of operational stoppages and downtime. A modern DCS system can mitigate these risks. Photo courtesy: Rockwell Automation

The average U.S. hydroelectric plant has been operating for 64 years. Such a lengthy service record shows the plants have staying power. But it also invites questions about aging hydro control systems.

The need for station and unit control reliability is critical in these decades-old plants, especially as power producers seek to maintain competitive and profitable plant operations amid declining peak generation prices. But their aging or obsolete systems, combined with the lack of operational and diagnostic information available in those legacy systems, can make excellent reliability control elusive. Many hydroelectric plants today use outdated control and electrical systems.

As a result, these plants experience a greater risk of operational stoppages and downtime. Operators are more likely to face support challenges and difficulty with maintaining regulatory compliance, in addition to spending time and resources performing manual data collection and reporting. And as these systems reach the end of their useful life, they must be replaced.

Modernizing to a contemporary, whole-station, unified control system can alleviate these challenges and facilitate tighter integration between unit control and associated subsystems.

If your hydro control systems are due for replacement, consider upgrading them to a modern distributed control system (DCS). A modern DCS system offers more than centralized plant control, monitoring and reporting. It can also tap into industrial Internet of Things (IIoT) data derived from your equipment to give operators a deep understanding of real-time events. This can help them make informed decisions, on-site or remotely, and optimize your station’s performance.

Rethinking Modernization

Modernization is an effort that involves more than migrating from an old legacy system to its modern equivalent. It often requires rethinking applications and upgrading multiple technologies within a plant. In the end, however, it can transform a hydroelectric plant’s processes and help reposition its operations for the next 20 to 30 years.

In fact, power producers can more efficiently manage their assets to help improve their bottom line by modernizing old or obsolete automation systems that make up only a fraction of their bottom line. Modernization can also help producers leverage advanced analytics to monitor and optimize multiple plants across their fleet.

The power generation industry has long been a leader in data collection and analytics, as well as regulatory compliance. Modernization continues that reputation by leveraging the power of the IoT. For instance, by linking power production and equipment performance data to information systems, power producers can gain access to real-time metrics and predictive insights into virtually every aspect of a station’s operation. This improved visibility can help producers increase reliability, reduce maintenance, achieve more precise control, and improve diagnostic capabilities.

For plants undergoing modernization, the key is to understand not only what new technologies they should leverage, but also what business improvements they can deliver. This is especially important in today’s competitive world of generation, where justifying capital spending on automation is becoming more challenging and requires a solid business case.

Digitally Transform Your Plant

Bulk-electric-system plants lag other industries when it comes to connecting and digitizing operations. But plants that have begun the journey are proving it’s better late than never.

Just look at the case of one generation plant. It was hobbled by spurious trips that impacted generation and manual reports that took hours to produce every day. The station transitioned to a scalable, information-enabled DCS. And it replaced its proprietary network with an open EtherNet/IP™ network. After making these changes, the station saw nuisance fail-safes drop by nearly 90 percent and restart times improve by 25 percent.

In hydroelectric unit operations, the ability to access, analyze and act on data can create a richer operating environment at all levels of the station. Operators can make real-time comparisons of turbine performance and drop reaction time for dispatching. With broad-based deployment of integrated intelligent condition monitoring technologies, technicians can drill down into unit equipment health to monitor and diagnose assets. Furthermore, executives can connect global fleets of hydro, fossil and other assets to track and compare their performance over time.

A modern DCS system helps makes this all possible.

Define Your Strategy

Some strategic decisions must be made before you can upgrade your hydro control system. Key questions to answer include:

What is the short-term, mid-term and long-term vision for the facility?

Each journey to a connected operation is unique for every facility. For instance, a short-term objective for some power producers may be to upgrade the unit controls with their plant. The long-term vision object, however, may be to create a tightly integrated plant control system that incorporates the excitation system, governors, turbines, control system, vibration monitoring, and power distribution and protection equipment.

Will you replicate or improve on your current DCS?

Replication means replacing automation hardware with new components, but keeping all functionality unchanged. This approach may be less expensive upfront, but it can have a higher lifecycle cost because it delivers minimal operational improvements.

Making improvements to your DCS requires more initial investment than simply replacing components, but it has the potential to offer a far superior return. For example, you could configure new HMI displays to improve operator visibility into asset performance, allowing improvement on the time it takes to respond to alarms and recognize the root-cause of issues. Another improvement could be writing new controller code to automate manual operations and improve process control. Improvements to your DCS like this can help decrease downtime, enhance safety and reduce risk.

Will your upgrade be vertical or horizontal?

In a horizontal upgrade, you replace each turbine automation system in a sequential fashion. In a vertical upgrade, you replace the turbine automation system in conjunction with the upgrade to its associated systems, such as excitation, vibration monitoring and ESCADA.

“Making improvements to your DCS requires more initial investment than simply replacing components.”

This decision is often driven by your plant configurations and generation commitments. For example, you may have three turbines that supply power to an industrial facility, and two turbines must remain in service to meet production requirements. In this case, a horizontal upgrade approach would make the most sense to make sure two turbines are always available to supply power.

Will you upgrade all at once or with a phased approach?

Upgrading your entire DCS all at once is the simplest to execute. It also has the lowest overall purchase and installation costs. But enduring all the required downtime in one period is often too much for plants.

Spreading the downtime out across multiple periods is usually preferable. Specifically, a three-phase migration strategy that replaces HMI, controllers and finally I/O can spread your migration costs out over a longer period, minimize your risk, and reduce the amount of downtime your plant experiences.

Modern and Secure

The number of reported cyber-attacks on critical infrastructure has been on the rise in recent years. Security must be a non-negotiable element of your hydro control-systems upgrade project. Your strategy should be comprehensive and strive to:

• Safeguard your intellectual property.

• Protect against intrusions that threaten productivity, quality, and worker or environmental safety.

• Maintain critical systems on which populations depend.

• Achieve network availability and avoid network-related downtime.

• Support, while properly controlling, any remote access to your operations.

A good place to start is with the NERC CIPTM Reliability Standards. Familiarize yourself with the standards and how they apply to your facilities, systems, processes and workforce. Also, conducting a security assessment will help you understand the risks and areas of vulnerability that exist within your organization.

When it comes to implementing security, adopt a defense-in-depth approach. It’s a multilayered security approach based on the notion that any one point of protection can and likely will be defeated. It uses physical, electronic and procedural safeguards across six layers:

1. Policies and Procedures

2. Physical

3. Network

4. Computer

5. Application

6. Device

Finally, don’t overlook something as basic as working with trusted vendors. They can be just as integral to helping meet security goals as they are to your production, safety or quality goals. Request that all vendors disclose their security policies and practices, and ask if they follow core security principles when they design products.

There is an abundance of available industry resources that power producers can take advantage of to help bolster their security efforts. Converged Plantwide Ethernet (CPwE) reference architectures from Cisco and Rockwell Automation, for example, provide useful guidance for managing network-access security and addressing unknown risks.

Make the Most of Your Replacement Project

Aging hydro control systems will need to be replaced sooner rather than later. Upgrading to a modern DCS system will allow you to get the most from your replacement project. By combining centralized control with production intelligence, operators can get the most from their plant, as well as new and emerging IIoT technology.