GenView Controls Approach
This page contains detailed information on how our GenView software works.
If you are looking for more general information, click here!
The GenView Cogeneration Control is designed to operate an unmanned cogeneration site. The system is designed to provide reliable control, protection, remote administration, and data collection. These goals are accomplished through the use of microprocessor based hardware running on an embedded operating system. The hardware is selected from off-the-shelf vendors for production scalability. The software is customized to specific generation units but written generic enough such that it can be applied to any reciprocating engine (1 MW or less is the design spec) based cogeneration site without reprogramming the system but through skilled user level configuration.
The center of the system is based on an expansive register set that holds, and constantly updates, the operating parameters of the unit. A partial sample of this structure type is shown on the right.
The register sets are organized in blocks with different purposes (unit operation, synchronization, heat calculations, protection settings, statistical data, etc.). The system updates these registers and uses the information in downstream calculations and operation decisions. These register data are accumulated using sub-systems and sensors designed on the basis of accuracy and cost-effectiveness.
How GenView Protects Equipment:
The protection of the system is accomplished through a series of Boolean equations entered by the user. In the most basic form, this table of equations is empty and a skilled operator can load any protection statement based on all the available register sets. In real sales applications, a set of factory created equations would be entered and protected. The user could add additional protections, but could not remove the factory entered set without the factory passwords.
Using the picture in the upper right as a guide, the format for an equation to limit jacket temperature could look as follows:
IF Jacket Temp > 196 FOR 1.0 THEN SOFTSTOP.
In this equation, the capitalized words are in the framework while the italicized words are picked from drop-down menus. Finally, the number (in this case expressed as 196°F) is entered manually as well as the delay time in seconds (0 can be entered for no intentional delay). The system would monitor the data contained in the ID number 81 of Unit Block 1 where the output jacket temperature would be held. When the logic equation is read TRUE then a soft stop would be generated for the unit if the condition persisted for more than one second.
With this system, ANY monitored point could be used as a protection point, thereby allowing for new sensors and various schemes to be developed within the confines of the software.
Types of Stops
raditional generator control systems have two types of stops. The first is a standard shutdown, where the unit ramps down the kW level to approximately 5-10% of the rated value, performs a cool down, and finally turns off the engine. The second is the “Hardstop,” the typical result of all safety shutdowns; where the connecting electrical breaker is opened while the engine is immediately stopped.
Due to the number of nuisance faults (alarms) created by the Utility parallel application, we have found that many units can be “hard-stopped” several times a day while running at full load and temperature output. The most noted issue is with reverse power protection systems required by most US Utilities for non-inverter based generation.
As a result of these trips, a third type of stop has been created. The De-Energized Softstop was created to provide some mitigation to the ill-effects associated with multiple “Hardstops” daily to fully loaded reciprocating engines. The operation of the De-Energized Softstop is to issue a lower speed command to the speed controller at the same time an open breaker command is issued. The result is the engine load is removed immediately without an over speed condition. Once the load is off, the engine can perform a normal idle cooldown.
Through the use of these stops, it was determined that only a very few faults actually required a hard stop, and that most issues could be soft stopped. The GenView system allows the factory/user to choose the stop type, and even create levels of urgency such that a warning is issued at one set point, a soft stop at another, and a harp stop at still another. For the purposes of simplicity, this is typically not set up for each fault equation, but can be very useful when troubleshooting operational anomalies.
Other Metrics
Beyond the basics of monitoring the engines performance, output, temperatures, flow rates, heat rates and checking oil levels the software is already set up to monitor the following:
BTU Output
Intercooler input/output temp
Manifold pressure
Pre-Catalyst temperature
Pyrometers for cylinder analysis (if engine equipped)
Shutdowns
Breaker operations
+/- kWhs produced
Number of engine starts
Hours until maintenance is required
3Ø power factor
3Ø voltage/frequency/current/kW/kVA/kVAR
Total kW/kVAR/kVA
Zero and Negative sequence voltage/current
User added Digital and Analog sensors
Run Time
Total efficiency
If your application needs additional sensor data to function, this can be arranged. Please contact us for more info.
Special Operations
Derate
The system will have the capability to derate based on ambient or charge air temperatures. A rule is created to derate the system X kW per excess Y °F above Z temperature. As an alternative, if the charge temperature is too high, the unit can derate directly to a fixed level such as 80% of rated output.
Manifold pressure mapping
The system will have the ability to alarm or shutdown based on factory settable manifold pressures in response to kW output. The factory will input a manifold pressure range for each power level (100%, 80%, 60%, 40%, and 20%). Pressures outside the range for a given kW will trigger alarm and shutdown after a set delay. A service tech can be given the capability to override the protection for a brief period of time.
Operational Metrics
Cogeneration systems require extensive measurement tools to determine if they are meeting operational expectations. Some of these requirements are from outside agencies while others are required to compare the operation of one system to another.
The basic metrics for output are:
Run hours
kWh produced
BTU produced
BTU used
BTU delivered to three different customer loops
Number of starts
Number of breaker operations
FERC efficiency percentage
Total efficiency percentage
These values are stored for a day/month/ and total periods. The system can be set for a folio day to roll the data to a monthly file that is kept for 12 months.
Other metrics are necessary to compare systems to others at different sites:
% Availability – how much of the time is the unit ran versus the amount of time passed.
Gross Capacity Factor – How many kWh are generated versus how many could have been generated during the same time period at rated capacity.
Maintenance
The system is set to count down hours for a maintenance interval. As the count down nears completion, emails are generated to indicate the impending condition.
When the system is to be maintained, the service technician will place the unit in maintenance mode. This mode will stop the system normally, but also activate a maintenance clock and maintenance log entry to show when the system was placed in the mode. When maintenance is completed, a log entry will be made of the end time, and the system will restart itself. The maintenance logs, as well as the alarm and operation logs, are available to be downloaded remotely. They can maintain several months of operations and alarm data and at least a year of maintenance data
For additional info, technical or otherwise, please contact us using the listed contacts or the form below.
Interlocks
One of the UL2200 requirements is for non software logic shutdowns on the system. While the software incorporates a watchdog system that immediately “hardstops” a unit, due to the UL requirement an input such as loss of oil pressure (switch) would override the software and stop the operation of the unit.
Interlocks
One of the UL2200 requirements is for non software logic shutdowns on the system. While the software incorporates a watchdog system that immediately “hardstops” a unit, due to the UL requirement an input such as loss of oil pressure (switch) would override the software and stop the operation of the unit.
Mechancial
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High Jacket Water Temp
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Thermister based temperature probe. Set points for alarm or shutdown expressed in °F (°C is an option). A delay can be added to allow a condition to persist or verify that the collected data point was not an anomaly.
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High Jacket Water Cutoff
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Digital switch to hard stop the unit if the temperature is exceeded leaving the engine jacket.
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Low Oil Pressure (gauge)
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Pressure sensor resistive based probe. Set Points for alarm or shutdown expressed in PSIG (bars is an option). A delay can be added to allow a condition to persist or verify that the collected data point was not an anomaly.
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Low Oil Pressure Cutoff
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Digital switch to hard stop the unit if the oil pressure is below the sensor mechanical set point.
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High Charge Temp
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Placed between the throttle-body and the intake manifold.
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Used to warn against or stop possible detonation.
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Thermister based temperature probe. Set points for alarm or shutdown expressed in °F (°C is an option). A delay can be added to allow a condition to persist or verify that the collected data point was not an anomaly.
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Cogen Out Temp
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Used to determine if there is a flow problem or problem in the exhaust gas heat exchanger.
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Thermister based temperature probe. Set points for alarm or shutdown expressed in °F (°C is an option). A delay can be added to allow a condition to persist or verify that the collected data point was not an anomaly.
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High Oil Temp
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Used to alarm against or stop oil from being damaged.
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Thermister based temperature probe. Set points for alarm or shutdown expressed in °F (°C is an option). A delay can be added to allow a condition to persist or verify that the collected data point was not an anomaly.
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High Cabin Temp
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Used to detect air flow restriction or engine anomally.
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Thermister based temperature probe. Set points for alarm or shutdown expressed in °F (°C can be an option). A delay can be added to allow a condition to persist or verify that the collected data point was not an anomaly.
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High Cabin Temp Switch
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Used to detect fire
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Digital bimetal sensor.
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Low Oil Level
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Used to alarm against running out of make-up oil.
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Analog tank level in the day tank that can be calibrated to gallons.
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Low Coolant Level
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Site glass switch to warn when the system is running out of coolant and shutdown.
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Overspeed
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System monitors the MPU for speed. Can alarm for over speed at a fixed value or delta speed (1805-1795) = 10 delta speed useful for determining if a speed governor has become unstable.
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Cogen Flow
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Used to detect pump or leak problems.
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Flow meter or differential pressure switch
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High Post Exhaust Temp
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Used to detect problems with the Catalyst.
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Thermocouple based temperature probe. Set points for alarm or shutdown expressed in °F (°C is an option). A delay can be added to allow a condition to persist or verify that the collected data point was not an anomaly.
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Low Battery Voltage
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An analog voltage signal checks battery voltage to determine if it is charging properly or if the onboard battery maintainer is having problems.
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Gas Leak Detector (gas engine)
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Detects low to medium concentrations of natural gas and alarms the system for shutdown.
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Input Fuel Pressure (gas engine)
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Measures gas pressure input to verify pressure necessary for proper emission control.
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Fuel temperature sensor
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Provides fuel temperature for input to the injectors. Can be alarmed if too hot.
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External trip
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The system looks for an external device trip from an ignition or fuel/air ratio device that could impact operation.
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Loss of sensor or bad data
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The system monitors communication to sub-systems and can trip if the system is not providing data or is providing bad data.
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Electrical
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27/59 Under/Over Voltage
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Used to protect against improper voltage regulation.
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Set at two points for a short and long term trip
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81 o/u Over and Under Frequency
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Used to protect against poor frequency regulation
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4 set points 2 under and 2 over for different time characteristics.
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32 Anti-motoring
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Used to protect against power imported to the alternator stem. Possible prime mover problems.
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21 Auto-Synchronizing
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Sets the unit frequency faster than the Utility allowing the system to reach synchronization windows in a timely fashion.
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25 Sync Check
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Verifies the equipment is synchronized with the other source before allowing the interposing breaker to close. Sync window is adjustable to meet engine size requirements and Utility requirements. (Note: when complete will be tested to PG&E standards to eliminate additional 21/25 device currently required of all engine manufacturers.
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47 Negative Sequence Voltage
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Protects against closing the interposing breaker in the reverse rotation.
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Can also detect phase faults
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51 Over current
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Limits the power output of the unit.
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2 set points for short and long duration.
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