The present invention relates generally to the field of control of hydroelectric power generation installations, such as dams and the like incorporating one or more power generating turbines and flow bypass structures. More particularly, the invention relates to the monitoring and control of such a facility to enhance the survivability of fish populations in the vicinity of the facility that may be entrained into and pass through the turbines and flow bypass structures. The invention also relates to the control of a power production system, such as a system incorporating several power generating installations, capable of enhancing fish survivability and accommodating an overall water management program, while optimizing power production levels in the overall system.
Various techniques have been proposed for controlling and optimizing performance of turbine-power generating facilities, particularly facilities incorporating Kaplan turbines. Such techniques generally accommodate the influence of various operating parameters on turbine performance and may seek to optimize power production or efficiency of a turbine unit by properly adjusting the parameters, such as wicket gate and/or blade positions, known to influence turbine performance. The influence of the adjusted parameters on performance is typically known from past performance data, model testing, or empirical results of tests actually performed on specific turbine units. Such techniques allow the operation of turbine units to be manipulated so as to optimize their performance either automatically or by operator intervention.
Improvements in turbine optimization techniques have included systems for considering the influence of a large array of parameters on the performance of individual turbine units and the overall power production facility. In one such system, a multi-dimensional, or xe2x80x9cN-dimensionalxe2x80x9d cam is developed, based on site information and measurement, including dimensions for various operating parameters such as head water elevation, tail water elevation, flow rate, power output level, location of a turbine unit in an installation, (e.g., across a stream) and operating data on neighboring turbines in an installation. The parameters form an N-dimensional array or matrix including cells corresponding to the various combinations of ranges for each parameter. Each matrix location is then populated with information indicative of the relationship between gate and/or blade positions and the various operating parameters of the turbine. Over time, the N-dimensional matrix is thus populated with optimal gate and blade settings for each combination of parameter ranges. Moreover, various approaches can be used for identifying the optimal gate and blade settings for each matrix location. Such approaches include the use of penalty functions assigned a value to each parameter such that the optimal gate and blade positions will be determined to minimize an overall cost function.
As improved control systems have become available for power-generating turbines, adding additional sophistication and potential for enhanced control of individual turbine units and installations, increasing emphasis has been placed on the impact of power-generating installations on the environment, including on wildlife. Specifically, improvements to the physical structure of turbine units have been proposed to enhance the statistical probability for survival of fish that pass through the units during operation. However, adjustments of controlled parameters to further enhance the statistical probability for fish survival has lagged significantly behind such developments. This tendency has probably been influenced by a perception that regions of optimal efficiency for operation of turbines generally correspond to regions of optimal fish survivability. While this may sometimes be the case, it appears that a more informed approach to control of turbine units should account for the influence of controlled parameters on both the power production level and efficiency, maintenance and fish survival predictions considered as separate, although interacting, influences on the system. Heretofore known control systems, however, have not been equipped to consider such factors and to subsequently control turbine settings based upon their combination. Moreover, even if modifications in turbine operation could be made to enhance fish survivability, known control systems are not equipped to account for the impact (e.g., economical, environmental) of such modifications in such a way as to adequately inform facility management.
Other drawbacks of existing control systems result from their limited control scope, both in terms of geography and controlled parameters. In particular, most known control systems typically operate on a single turbine unit or bank of turbine units. Although systems have been proposed for managing multiple dams, such systems generally take into account only revenue generating parameters, and not environmental impact variables. Consequently, such control systems are not well suited for implementation of system-level water, fish and power management and planning schemes. Moreover, because heretofore known control systems have concentrated on operation of the turbine units and associated power generation equipment, they are not well suited for altering other operating parameters, such as those relating to spillway and fish bypass structures, in an integrated approach for implementation of water and fish management schemes.
Other known control systems have attempted to alter the behavior of fish rather than modify operation of the turbines. One such example is disclosed in U.S. Pat. No. 4,932,007, issued to Suomala. In all these known systems, however, the emphasis has been on guiding fish away from the turbines and/or toward fish bypass structures. Even assuming the facility is provided with fish bypass structures, however, they might not be available for some reason such as when economic constraints (e.g., low water levels or high energy costs) or other constraints (e.g., mechanical problems or maintenance) restrict or completely prevent the discharge of water therethrough. In such cases, there may be little or no choice but to send the fish directly through one or more of the turbine units.
In view of the above, there is a need for an improved system for controlling operation of a power-generating turbine unit, installation, and system, wherein fish survivability is considered as a separate factor impacting the desired settings of controlled parameters, such as wicket gate and blade positions, as well as operation of spillway and fish bypass structures. There is also a need for a system which can provide both planning and monitoring functions, as well as real-time control of a turbine unit or installation based upon both long-range knowledge of fish behavior and upon immediate or short-range knowledge of fish location and movement. There is further a need for a system that is capable of altering fish behavior in a coordinated manner with modifications to turbine operation.
The present invention features a novel monitoring and control system for power-generating turbine units, installations and systems, consisting of at least one turbine unit associated in certain cases with flow and fish bypass structures, designed to respond to these needs. The system is capable of monitoring fish location and movement via sensors positioned about the installation. In a preferred configuration, the sensors provide an indication of both fish location (position in a pond or stream and depth within the water) and, where properly instrumented, of fish type and school density. The information is used to monitor movement over time both in near and far fields relative to the installation. The information is collected and stored in a long-range database for future reference. Fish location data is also collected in a near field related to immediate location of fish within a relatively short distance surrounding the intake to a turbine unit. Information on the near field is used both to update and correct far field data and to impact, in a relatively immediate manner, operation of the turbine unit.
Data relating the statistical probability for fish survival through a turbine unit and bypass structures is preferably stored in an N-dimensional matrix along with other parameters for the turbine installation. Such data provides an indication of fish survival rates as a function of the position of control surfaces, such as blade and gate positions for Kaplan turbine units. With appropriate sensor capability, the data indicative of fish survival rates may also be a function of the position of the fish relative to the turbine intake structure and/or the route through the turbine unit. In a preferred embodiment, the data indicative of fish survival rates is evaluated in real time to balance the operation of the turbine units with that of bypass structures to appropriately weigh the impact of fish survivability on operation of the turbine units. The control of the system is then preferably modified based upon changes in the near and far field data. For example, the penalty function for fish survivability reductions can be increased in a linear or non-linear way to more heavily weigh fish survivability when significant densities of fish are located at positions in the near field known to result in entrainment of significant quantities of fish into turbine units. Thus, near field data and fish survivability based upon such data are used to override other performance-influencing factors when fish entrainment into the unit is predicted as imminent.
In addition to, or instead of, altering the operating point of the turbine units, the near and far field data may also be used to modify the behavior of the fish. More particularly, when the near field data indicates that a significant number of fish are likely to be entrained in the turbine units, the system may attempt to direct or steer the fish toward particular turbines and/or toward special zones within the turbine intakes that will provide the fish with the highest probability of surviving passage through the turbine units.
The near and far field data are also used as a predictive and planning tool for operation of the turbine installation, with knowledge of fish movement and behavior over longer ranges of time, such as weeks, months, seasons and years. When implemented on a system or stream-wide level, the system permits adaptation of the operating point of turbine units as well as water and fish bypass structures and the behavior of the fish, to realize desired fish survivability targets while optimizing energy production levels to the degree possible given the fish survivability targets. Moreover, when the system predicts that the optimal or target levels of fish survivability have been achieved and/or can be achieved by modifying fish behavior alone, remaining adjustability of the control surfaces (in a xe2x80x9cfish survivability-confinedxe2x80x9d region) may be optimized to provide maximum power output, maximum efficiency, maximum revenue, or other target.
Thus, in accordance with a first aspect of the invention, a system for enhancing fish survivability in a hydroelectric installation has at least one power generating unit positioned across a body of water between an upstream water source and a downstream water discharge region. The unit includes a turbine supported for rotation in response to water flowing therethrough and a power generator operatively coupled to the turbine for generating electrical power through rotation of the turbine. The unit includes control surfaces selectively orientable to control power generated by the unit. The system comprises means for detecting fish likely to be entrained by the turbine, as well as means for directing the fish toward a selected area of the turbine that corresponds to a preferential flow path through the turbine.
In accordance with a second aspect of the invention, a system for enhancing fish survivability in a hydroelectric installation has at least two power generating units positioned across a body of water between an upstream water source and a downstream water discharge region. Each unit includes a turbine supported for rotation in response to water flowing therethrough and a power generator operatively coupled to the turbine for generating electrical power through rotation of the turbine. Each unit includes control surfaces selectively orientable to control power generated by the unit. The system comprises means for detecting fish likely to be entrained by at least one of the turbines, means for determining which of the at least two power generating units provides a higher probability of fish surviving passage therethrough, and means for directing the fish toward the turbine that provides the higher probability of fish survival.
In accordance with a third aspect of the invention, a method for enhancing survivability of fish passing through a hydroelectric installation having at least two power generating units is provided. The two power generating units are positioned across a body of water between an upstream water source and a downstream water discharge region. Each unit includes a turbine supported for rotation in response to water flowing therethrough and a power generator operatively coupled to the turbine for generating electrical power through rotation of the turbine. Each unit includes control surfaces selectively orientable to control power generated by the unit. The method comprises steps of detecting fish likely to be entrained by at least one of the turbines, determining which of the at least two power generating units provides a higher probability of fish surviving passage therethrough, and directing the fish toward the turbine that provides the higher probability of fish survival.
In accordance with a fourth aspect of the invention, a method for enhancing survivability of fish passing through a hydroelectric installation having at least one power generating unit is provided. The power generating units are positioned across a body of water between an upstream water source and a downstream water discharge region. The unit includes a turbine supported for rotation in response to water flowing therethrough and a power generator operatively coupled to the turbine for generating electrical power through rotation of the turbine. The unit includes control surfaces selectively orientable to control power generated by the unit. The method comprises steps of detecting fish likely to be entrained by the turbine, and directing the fish toward a selected area of the turbine that corresponds to a preferential flow path through the turbine.
In accordance with a fifth aspect of the invention, a system for enhancing fish survivability in a hydroelectric installation has at least one power generating unit positioned across a body of water between an upstream water source and a downstream water discharge region. The unit includes a turbine supported for rotation in response to water flowing therethrough and a power generator operatively coupled to the turbine for generating electrical power through rotation of the turbine. The unit includes control surfaces selectively orientable to control power generated by the unit. The system comprises means for correlating at least one desired position of the control surfaces with enhanced fish survivability as fish pass through the turbine, means for detecting fish presence in the water in both near and far fields relative to the installation, and means for placing the control surfaces in the at least one desired position upon detection of the presence of fish in the water.
In accordance with a sixth aspect of the invention, a method for enhancing fish survivability in a hydroelectric installation having at least one power generating unit is provided. The generating unit is positioned across a body of water between an upstream water source and a downstream water discharge region. The unit includes a turbine supported for rotation in response to water flowing therethrough and a power generator operatively coupled to the turbine for generating electrical power through rotation of the turbine. The unit includes control surfaces selectively orientable to control power generated by the unit, the installation including sensors capable of detecting the presence of fish in near and far fields relative to the turbine unit. The method comprises steps of correlating at least one desired position of the control surfaces with enhanced fish survivability as fish pass through the turbine, detecting fish presence in the water in both the near and far fields, and placing the control surfaces in the at least one desired position upon detection of the presence of fish in the water.
In addition to the above-described aspects, other aspects and features of importance to the present invention are specifically recited in the various dependent claims.