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Power Management. Fred Gibson Gibson Technologies cc www.gibsontech.org.za. Basic Energy Concept. Energy Management. What is energy management? One meter at the main incomer. Report at the end of the month. Want to check up on the supplier. Driven by an idea of a saving somewhere???
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Power Management Fred Gibson Gibson Technologies cc www.gibsontech.org.za
Energy Management • What is energy management? • One meter at the main incomer. • Report at the end of the month. • Want to check up on the supplier. • Driven by an idea of a saving somewhere??? • Closed demand control system. • Black box sitting in the corner • Dot matrix printer with the ink dried up years ago • Cannot adjust. No control over fixed philosophy Too Late Accounting Based Approach
Energy Management • What comes next? • One meter at the main incomer. • Continuous updated data on a machine. • Ability to react in time. • Driven by a knowledge of achievable savings • Changeable demand control system. • Computer with SCADA and real time info • Trending showing fresh data • Set Priorities, move limits….choice • Ability to lock or limit freedom, but override on intelligent decision • Write fixed philosophies with adjustable set points Pro Active Active Approach
Demand Control • Load Shedding • Turn non critical loads off • Plant specific • Example :
Wheat Mill Three Mills may be run individualy or together C-Mill Example Intake has bins as buffer and can be stopped at times with proper planning
Two Flow Paths Shedding in Process Two Flow Paths Note the current drawn by each motor
Demand Control • Load Shedding • Turn non critical loads off • Plant specific • Example : • Adjustable control • Smooth • Arc and Induction Furnaces • Example :
Continuous Control • Philosophy • Before: • Furnace power controlled by POT • POT adjusts 0-10V signal to controller • Operator has full control. Example 0 – 3000KVA • After • Read POT Voltage into Analog Input • Write Analog output to Furnace controller • When Shedding, read 100% of POT Value in • Write only 90% to controller • Shed 300KVA
Smooth Shedding • With continuous control we can achieve almost perfectly smooth control of demand • Maximum demand window runs for 30min • Calculate in PLC a 25min Window • Leaves 5min to shed progressively • Ease the power back up • Run your plant at peak power • Do not cross the maximum demand target
Actual Case KVA Without Shedding KVA With Shedding Thermal PLC Target IT Furnace AEG Furnace Shed Percentage limited to 40%
Energy Management • What are you missing? • All this is demand based control (KVA). • You need to save energy (kWh). • Then you need to know where your energy is going. • Use 80/20 Principle. • Cutting KWh can be very expensive. • Screening windows • Insulating heat sources • Replacing inefficient machines • Most savings to be had are mechanical. • We just pay for them on our electricity bill. • This is why we choose the right tool for the job
Right Application Metering and Control Roaming Fault Analysis Fixed Power Quality Monitoring
The PLC solution Build an Ethernet backbone Need to know CB Open or Closed Status Plug an Input Card into the PLC Need a Power meter Need to open or close CB’s Plug a Power meter into the PLC Plug an output card into the PLC Plug in five if you need Need a BUS TIE BUS Controller Need a Power Factor Controller Need a Generator Changeover Controller Need a Safety interlocks on TIES and Rings No Communication Gateways, all Ethernet PROGRAM IT INTO THE PLC Measure your transformer core temperature Plug a PT100 Card into the PLC Need to Look after the load on your Generator The Power values are available in your PLC + The PLC Controls
PLC CODE Makes it easier to calculate averages and complex mathematics
Brainstorm Valuable Ideas See and trend all your power meters in the control room Visualise your power system Animate breaker statuses Use trip counters, timers and load Data to schedule maintenance Need power to expand? Eskom says no. Shift, schedule, save, shed and make a plan G Switch remotely, Keep personnel out of harms way Capacitor condition monitoring See the load flow, know if your equipment will hold Understand where energy is used, focus on solutions, measure, compare Make safe, informed switching decisions on rings and bus ties Calculate electricity cost as a percentage of production cost Save all your power system details , specs, part numbers, procedures, Escalation procedures etc in one place Schedule Load shedding based on Time, Priority, Load, Trip Conditions And Thermal feedback from your Transformer. Log all events in the system Build load and voltage history over many years. Know how much your Power system can take when you want to expand. Generate alarms on Status and level, proactively Avoid crippling penalties, by stopping production When your kWh budget is spent. Make a management decision. Incorporate production schedules' In your energy management scheme Publish all info on Intranet Read last trip data directly from your protection relay Send E-mails, SMS’s based on Events. Call Artisans out. Monitor your generator’s temperature, Diesel level and Battery voltage And make sure it will be ready when you need it.
Why Wonderware ? • Wonderware makes all the above possible • Tried and tested software which is scalable • Start with your immediate needs • Upgrade tag base, Add software • Install more power meters • Slide more PLC cards in easily • Connect to any commercial protocol • All as you need when you need • No Limits
The Object Solution • Use object orientated software • Build Power meter object • Will gather data from field • Will display all values available from meter • Will handle functions like reset max registers, kWh etc. • Will trend, log into database, alarm • Build Circuit Breaker object • Will read status • Will do operations counter • Will log operations and times • Build all objects once and us them all over • Update your object and your whole system will be updated and deployed
How to start • Brainstorm your immediate concerns, not wants • Choose a philosophy that will address these concerns • Plan and engineer the solution to allow for expansion and wants of the future • Plan how you will store the information • Think of who must see and react…..When? • Think of who will be the Energy Manager • When you have some data then Analyse • To get the backbone system running is the most difficult, your wants later will be easier
Conclusions • I hope I have given you some idees of what is achievable with energy management. • The most difficult part is to define what your needs are. • Don’t think you will not want the extras later. • If you plan the system with the end in mind, you will be able to achieve a lot without much hassle.
