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Improved Governor Response at the Dinorwig Power Station

A HydroVision International 2013 Technical Paper of the Year | View Award

Dinorwig Power Station, located in North Wales, UK is one of the largest Pumped Storage facilities in Europe and has the capacity to generate electricity with six (6) 300MW pump generator units. These units make a significant contribution to ensuring the day-to-day stability of the UK, which relies on the Dinorwig Powerhouse to deliver rapid, consistent response. Upgrading the digital governor controls on Unit #1 resulted in reliable, accurate and faster response to a range of frequency excursions. This paper provides an insight to this achievement, which has re-enforced Dinorwig as one of the leading Pumped Storage plants in the World.

Authors: Greg Yohe with Toni Jones of First Hydro Company
Presented at HydroVision International 2013 – Denver, CO

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Why Hydro is Critical to Grid Stability

This presentation provides an overview of how generators on large electrical grids respond to frequency disturbances and describes why hydro is critical to a well-functioning grid. The concepts of primary, secondary and tertiary control are discussed, as are the varying – and in some cases extremely limited – contributions provided by other types of generation including: fossil, nuclear, reciprocating engines, wind, and solar.

Considering the current trend of increasing penetration of wind energy into electrical grids, this presentation will debunk current fallacies about the degree of grid support that is available from modern wind turbines and discuss the likelihood of wind farms voluntarily agreeing to generation curtailments to support real-time grid needs. Finally, this will present several concrete ways in which owners of hydro units can expand and strengthen their ability to provide – and get paid for – first-line-of-defense responsiveness to grid frequency disturbances.

Author: Matt Roberts
Presented at HydroVision International 2013 – Denver, CO

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Standardizing Governor and HPU Conversions Down Under

Mighty River Power (MRP) is one of the leading utilities on the North Island of New Zealand. They have been maintaining a collection of diverse governor and Hydraulic Power Units (HPUs) that are all original and date from the 1940s. Due to attrition and downsizing within the company, the number of technicians who know how to tune, adjust, overhaul and otherwise support these diverse mechanical and early analogue governor control systems has dwindled to the point where the utility was concerned a governor component failure could idle a unit for up to nine months.

In conjunction with their exciter/voltage regulator and protective relay upgrade programs already underway, in 2011 MRP initiated and funded a project to modernize their fleet of governor systems to be compatible with the new Unit / Plant Control and SCADA systems. This presentation describes how MRP developed and implemented a strategy to convert and standardize their governor and hydraulic systems.

The end goal is to modernize and standardize all 20 hydro units in their system, so that a small team of trained technicians can support these systems for decades to come, without having to “re-learn” the software, electrical and hydraulic interface at each plant. Likewise, their remote Dispatch Center will have Governor Control screens that are uniform and consistent.

Author: Roger Clarke-Johnson
Presented at HydroVision International 2013 – Denver, CO

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Mitigating the Costs of Equipment Failures in Modern Hydroelectric Control Systems

During the design phase of modernized hydroelectric control systems, there is often great concern and confusion surrounding the topic of equipment redundancy. Redundancy promises to improve system reliability, but comes with the upfront costs of additional equipment, significantly increased engineering costs, and the long term costs of increased system complexity. Unit availability at hydroelectric installations is critical to grid reliability, water conveyance and utility revenues; therefore unexpected unavailability commonly comes with hefty penalties in addition to lost generation revenues. Because of this the benefits of redundancy are often viewed as outweighing the costs.

While this is generally true for the largest of installations, it is not always the case for smaller plants. This presentation will look the continuum of methods which can be employed to improve control system reliability. Varying levels of redundancy will be examined, from simple component redundancy to full-blown triple modular redundant approaches.

Additionally, alternate means of mitigating the costs of equipment failures will be explored. These will include preventative maintenance plans, comprehensive personnel training and spare parts stocking strategies. Each tactic will be evaluated for its short and long term costs and its effectiveness in minimizing three metrics: Mean Time Between Failures (MTBF), Mean Time to Repair (MTTR) and Mean Time Between Forced Outage (MTBFO). To provide application examples, several recent hydro governor modernization projects will be studied. Details of the approach taken, comments from the plant owner on why their approach was chosen and lessons learned will all be included.

Author: Matthew Roberts
Presented at HydroVision International 2012 – Louisville, KY

Watch Presentation, part 1 | Watch Presentation, part 2

Automated Regression Methods for Turbine-Penstock Modeling and Simulation

Utilization of turbine-generator system modeling can provide distinct advantages when considering capital improvement projects in hydropower facilities. Such modeling both facilitates the decision-making process for turbine control modernization projects as well as the design and validation of specific turbine control systems.

Author: Gary Rosenberger
Presented at HydroVision International 2012 – Louisville, KY

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Untapped Opportunities for Grid Reliability Improvement

Hydropower generation has been shown to provide the most substantial component of Primary Frequency Control of any generation type in the Western Electricity Coordinating Council (WECC). Primary Frequency Control is an important component of grid reliability and as such is regulated by the North American Electric Reliability Corporation (NERC). This paper explores the untapped potential for increasing hydro’s role in improving grid reliability via Primary Frequency Control by adding or maintaining governor systems at smaller plants.

Author: Steve Wroblewski
Presented at HydroVision International 2012 – Louisville, KY

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Assessment Of Various Unit Control Architectures

Governor systems are required to always meet or exceed the performance and reliability requirements of IEEE 125 “Recommended Practice for Preparation of Equipment Specifications for Speed-Governing of Hydraulic Turbines Intended to Drive Electric Generators”, as well as meeting expanding NERC Reliability Standards. Very careful consideration must be given when designing replacement plant or unit controllers. Using real-world examples, this paper will describe the potential for current and future difficulties with this type of integrated control scheme, discuss situations where the integrated system strategy may be used successfully, and identify the critical issues to consider when developing a controls retrofit strategy.

Author: Alan Fox
Presented at HydroVision International 2012 – Louisville, KY

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Impact of FERC Rule #755: Frequency Regulation Compensation in the Organized Wholesale Power Markets

Secondary frequency regulation service, also known as Automatic Generation Control (AGC), is one of the tools regional transmission organizations (RTOs) and independent system operators (ISOs) use to balance supply and demand to maintain reliable grid operations. On October 20, 2011, the Federal Energy Regulatory Commission (FERC) issued Final Rule #755 regarding frequency regulation compensation in the organized wholesale markets. This final rule affects the compensation that energy providers receive for their services.

Author: Roger Clarke-Johnson
Presented at HydroVision International 2012 – Louisville, KY

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Operational and Performance Advances with Digital Governor Controllers on Multiple Needle Impulse Turbines

Multiple needle impulse turbines are among the most efficient designs of hydroelectric turbines, however are often restricted from reaching their full operating potential due to control limitations in their legacy governor systems. Mechanical, analog and early digital governors lack the ability to separate control of the deflector and the individual needles, which results in numerable operating obstacles: primarily poor needle control and the inability to realize the maximum efficiency of the turbine. Today, modern digital controllers and hydraulic controls allow for precise, independent positioning of the deflector and each needle, and therefore needle sequencing. With these key features, all of the aforementioned shortcomings can now be overcome.

Authors: Matthew Roberts with Mark Nunnelley of Pacific Gas & Electric Company
Presented at HydroVision International 2011 – Sacramento, CA

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The Impact of Hydroelectric Power on Grid Frequency Stability for the WECC Region

With the increased use of variable forms of generation such as wind and solar, there is increased concern not only about load matching, but grid stability itself. Hydropower plants often are proposed to back-up variable sources due to the ability of hydropower plants to store their fuel/energy. In addition to compensating for the hourly and daily variations in output from wind farms and solar plants, hydropower plants can also make significant contributions to grid stability through the capabilities of their governing systems.

Authors: Deepak Aswani, Roger Clarke-Johnson, Gerald Runyan
Presented at HydroVision International 2011 – Sacramento, CA

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Governor Upgrades for Grand Coulee’s Third Powerhouse

The US Bureau of Reclamation (USBR) Grand Coulee Third Powerhouse has the largest hydro units in North America at approximately 750MW each. Together they total approximately 4.5GW, making it one of the largest power plants in the world. Facing increasing difficulty obtaining spare parts for the 30+ year old analog governors used on these units, USBR decided to contract for turnkey digital governor conversions on all six units in this powerhouse over a period of three years. The governor project is scheduled in tandem with the installation of new voltage regulator/excitation systems.

Authors: Roger Clarke-Johnson, Bill Eberman, Scott Holden
Presented at HydroVision International 2011 – Sacramento, CA

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Large Scale Governor System Retrofits: U.S. Army Corps of Engineers, North Pacific Region

Throughout the Pacific Northwest the U.S. Army Corps of Engineers owns and operates 21 hydroelectric powerhouses. The mechanical and analog governor systems that control the turbines in these facilities include a wide variety of manufacturers: Woodward, Pelton, Voest-Alpine, and Allis-Chalmers. The turbines are predominately Kaplan type, but also include a number of Francis units. In an effort to enhance operational efficiencies the U.S. Army Corps of Engineers has begun the process of converting all of the 146 governor systems
to a standardized digital control platform with a common electro-hydraulic interface.

Authors: Deepak Aswani, Gary Rosenberger, Matthew Roberts
Presented at HydroVision 2010 – Charlotte, NC

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Redundant Governor Control Upgrade for Helms Pumped Storage

As part of a major plant upgrade, Pacific Gas & Electric (PG&E) is replacing the analog governors on three 404MW units at the Helms Pumped Storage plant. Because this is a critical plant, the new governor system features fully redundant PLC controls and feedback sensors, as well as redundant hydraulic control manifolds. This paper provides an overview of redundancy concepts and a description of the redundancy and fail-safe features included in the Helms governor design.

Author: Roger Clarke-Johnson
Presented at Waterpower XVI (2009) – Spokane, WA

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Technology Improves Rafter Habitat: Chili Bar Controls Upgrade

Redundant system improves downstream flow control at Pacific Gas & Electric (PG&E) plant.

Author: Dan Berrien, P.E.

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New Method for Improving On-Line Loading Rates on Mechanical Governors

Understanding and using the dashpot to improve on-line loading.

Author: Gerald Runyan
Presented at Waterpower XV (2007) – Chattanooga, TN

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Canal Flow Control Improvement in Central Valley

Digital controls improve flow control on irrigation canals.

Author: Nancy Kroner
Presented at Waterpower XV (2007) – Chattanooga, TN

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Overhaul or Upgrade: Governor Decision Factors

Methodology for deciding whether to maintain or upgrade.

Authors: Roger Clarke-Johnson and Scott Ginesin

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Governor Oil Pump Condition Assessment

Lack of recommended OEM pump maintenance can cause catastrophic failures.

Author: Alan Fox

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Power Grid Infrastructure Security Through Small System Dependability

Mechanical governors provide stability for SCE islanded system.

Authors: Nancy Kroner with Joel Preheim of Southern California Edison

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Articles

Monitoring the Health of Mechanical Governors

New test-based maintenance program implemented at PG&E.

Authors: Michael Mato and Gerald Runyan
Published in Hydro Review, June 2007

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Working to Solve Pelton Governor Instability at John Day Dam

For 14 years, the U.S. Army Corps of Engineers (USACE) experienced intermittent governor stability problems with units at its 2,160-MW John Day Dam on the Columbia River. Symptoms included hunting and difficulty synchronizing. It was discovered that the output voltage of the permanent magnet generator (PMG) was low, suggesting that the PMG needed to be remagnetized. American Governor Company (AGC) designed a special apparatus to remagnetize the PMG. Following remagnetization, the governors operated normally.

Authors: Roger Clarke-Johnson with David Shank, P.E. and Jack Dean of U.S. Army Corps of Engineers
Published in Hydro Review, November 2006

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Hydro Governors and Controls: A Perspective

Perhaps the most common hydro governor in the world today, the Woodward Gateshaft governor is now as it was then: “a simple, strong and durable” device capable of “accuracy and smoothness in the control of load changes.” Designed to last a hundred years, thousands of Gateshaft governors remain in use today, still functioning and largely unchanged after nearly a century of service.

Author: Gerald Runyan
Published online at Energy Central, October 2002

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Posters

Advanced Governing Algorithms at the Grand Coulee Third Powerhouse

A number of governing methodologies are available including Proportional-Integral-Derivative (PID), lead-lag, double-derivative, and other variants introduced by modern control theory. Unfortunately no variant is best suited for all conditions. For the Grand Coulee Dam’s Third Powerhouse governor upgrade, a fourth order lead-lag governor was used. For this particular application, a fourth order lead-lag controller provides superior feedback control over a PID type controller. This poster demonstrates the robustness comparison and is supplemented by data recorded from the actual governor upgraded at Grand Coulee Dam’s Third Powerhouse. This robustness and sensitivity analysis can serve as a model for other power plants.

Authors: Daniel Londono, Matthew Roberts, Paul Silva, and Reginald Smith
Presented at Hydro Vision International 2012 – Louisville, KY

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