Improvements in control and protection systems can cut costs in all areas of a plant, but installing the latest technology may not be the most beneficial route to take.
Protection and control systems technology has advanced further in the past 50 years than any other hydro plant technology. To help utilities find their way around the improvements that have been made in this area, US-based epri has produced a guide: Hydro Life Extension Modernisation (LEM) Guide, Volume 7, Protection and Control. This is one of a follow-up to a series of guidelines that were first issued by EPRI in 1989 to help utilities develop plant LEM plans.
EPRI’s guidelines are the result of an extensive review of literature on protection and control systems. According to EPRI, they are not to urge the utility to strive to maintain the whole hydro plant at the very forefront of the technology envelope, because such a goal would require continuous upgrading with unproven technology that could be detrimental to protection and control systems’ reliability. Instead they suggest a stepped approach to technological modifications that will best enhance system availability, reliability and maintainability and promote the development of integrated protection and control systems.
The technical subjects covered in the guide include:
• Protection and control systems.
• Programmable logic controllers.
• Human-machine interfaces.
• Event recording.
• Machine condition monitoring.
• Operating information and data acquisition.
• Communication networks.
• Control networks.
EPRI says that its series of LEM guidelines has adopted an approach that takes the user from establishing a base case, to pinpointing high value alternatives, to incorporating options in the overall LEM – and on through selection, procurement and implementation phases. Throughout the process the focus is on creating value by applying technologies that offer the created return. This means understanding the technologies and their application while keeping an eye on markets and matching technology to market demand. Automation can reduce costs and improve reliability in all areas of a plant, but it cannot be performed haphazardly.
Dale Gray is EPRI’s project manager. He went to the utilities to find out what they wanted from the guidelines. ‘Volume 7 was the guide they wanted first,’ he says. ‘It’s an area in which people believe you can get “more bang for your buck”.’
Gray says that the guidelines introduce a commercial and open-minded way of thinking for hydro operators newly-faced with deregulation. Volume 7 describes recent advances in protection and control technology, but from a business perspective.
BC Hydro formulated the guidelines on EPRI’s behalf, and has since developed a software package to complement them called TAPlogic. BC Hydro calls TAPlogic a renewals management system. It is intended to guide utilities through the process of upgrading aging assets.
TAPlogic enables decision support for short and long term business planning, which leads to cost-effective operations and optimised productivity. It also stores and integrates information about each hydroelectric asset, enabling users to screen, assess, manage and prioritise investment decisions. TAPlogic has two main functional components:
• A database of spending activities derived from condition surveys, performance assessments, risk evaluations, dam safety reviews, and business and other technical initiatives across the assets.
• An economic and financial model that assesses these activities based on user input and business evaluation criteria. TAPlogic presents results in the form of reports and graphics that support decisions, justify business cases, and drive project implementation.
The input to this software application is the extensive technical and financial information collected using methods and processes such as those outlined in Volumes 2 to 7 of the EPRI Guidelines. The model then aligns this engineering knowledge with economic and financial parameters to allow decision-makers to clearly understand the impacts of various life extension and renewals alternatives. TAPlogic has been designed to:
• Apply accepted economic and financial analytical frameworks to annual budgeting, long term planning, and short term decision analysis.
• Incorporate non-financial decision criteria to ensure that projects are analysed and ranked based on all of the business’ overall goals and objectives.
• Value the short and long term cash flows and profitability of individual production facilities.
• Allow the user to analyse the impacts of varying spending, operating conditions and market assumptions on cash flows and profitability, and review the impacts of decisions and scenarios at various operational levels.
• Complete standard capital and operating project analyses on individual projects or groups of projects, to assist in business case preparation.
BC Hydro’s power generation group uses TAPlogic to provide forecast financial information for individual production facilities and portfolios of facilities defined by rivers and/or geographic areas. It has provided decision-makers with prioritised, rationalised and ranked lists of renewals projects in a context consistent with divisional and corporate objectives.