Presentation on theme: "Electrical Power Generation, Transmission, Storage and Utilization"— Presentation transcript:
1 Electrical Power Generation, Transmission, Storage and Utilization Ray FindlayIEEE 2002 PresidentMcMaster University, Canada
2 Robert K.Green, President & CEO of UtiliCorp United “The utility of the future is multinational, carries its expertise into emerging parallel businesses, has the flexibility and willingness to unbundle, adapts readily to new structures and concepts, goes beyond its traditional borders to grow, and is an expert manager of risk.”
3 What’s in the Future? Global power Privatization Consolidation DeregulationFree market competitionEmphasis on capital, investment strategy and economics, including cost reduction
4 Technical Requirements Generation: need the lowest cost generation available to meet demandThere are many factors involved in this process, complicated, not only by technical considerations, but also by political considerations:Environmental considerationsMaintenance and operating costsInefficiencies as a result of transmissionRegulatory issues
5 Some Elements of the Competitive Power Market Energy network owners - transmissionEnergy tradersEnergy brokersMechanisms for exchangeWholesale energy pricingCost of energy tradingEnergy service providers - distributionRetail operations - supplyMarketing services
6 Challenges Aging infrastructure Maintenance & scheduling Power Quality & harmonic distortionAdvances in machine & drive designReducing transmission lossSystem complexityNetworked generation distributionBusiness VS engineering decision-makingEducational issues
7 Opportunities Generation asset management Efforts to optimize utilization of generation facilities according to market demandIncentive to increase efficiencies of power plants and systemsIncentive to rationalize maintenance schedules to minimize downtimeImprovement of communications among suppliers, and of monitoring systems
8 Transmission/Network Grids, A Problem Unbundling the transmission grid from both the generation and delivery creates a problem - by definition it must be a monopoly.Need to ensure open accessNeed for regulation and oversightNeed for maintenance & development of more capability as requiredDanger of fragmentation, congestion, tariffs, scheduling difficulties, etc.
9 The Retail Environment Role of the retailerOne, two, how many bills?Wholesale versus retailLarge customers versus small customersMultiple service opportunities: gas, electricity, water, financial services (credit)Methods of pricing for retail deliveryfixed term pricingspot market pricingregulated, capped or open access pricing
10 ControlWith large, multi-connected systems inter-tying substantial areas of the globe, communication and control become problemsDedicated communication linesInternet operation and controlDC generation/conversion transmission versus AC generation and transmission
11 CoGeneration Issue of small plants Interconnections as a virtual plant MethaneWind powerSolar powerTidal powerInterconnections as a virtual plantControl issuesSpecialized components
12 Power Quality Harmonics Distortion: power electronic loads, adjustable speed drives & switch-mode power suppliesElectromagnetic compatibilityComponent magnetics: machines, transformers, ACSR, etc.Power factor: displacement power factor versus true power factor
13 Power Factor Displacement power factor: PFd = Cos (/VfIf) True power factor:PFt = P/(VrmsIrms)For 100% THD on current, the maximum true power factor will be about 0.71
14 Measuring Power Quality Total harmonic distortion Irms/I1True power factorCommunications influence Gw2Ii2/IrmsCrest factor Vpeak/VrmsThere are several other special purpose power quality indices.
15 Harmonic SourcesSaturable devices include electrical machines, transformers, some transmission conductors, and fluorescent lights with magnetic ballastingPower electronic (switching) loads include switch-mode power supplies, PWM converters, voltage source converters, fluorescent lighting with electronic ballasting, computers, etc.Although not strictly a source, a resonant system can exacerbate harmonics - systems containing both capacitance and inductance. An example is an inductive load with power factor correction.
16 Voltage Sags in a Multisource Environment Motor starting, transformer energizing, faults and load switching can all lead to voltage sag.Normal clearing time for a fault is 2 or 3 cyclesClearing for a motor start can take 10 cyclesFor a load switch/transformer energize, it can take cycles
17 Voltage Sag Mitigation Strategies Reduce the number of faults. This can be accomplished by upgrading equipmentImprove the system. Loads susceptible to faults should be multi-sourced. Use high-impedance grounding with )Y transformers to reduce the effects of a single phase to ground faultInterface between system and load - installed additional equipment. Dynamic voltage restorer.Improve the load equipment
18 Power AcceptabilityTo ascertain power acceptability we can use power acceptability curves that measure the sensitivity of the load against voltage sags or over-voltages. The curves are logarithmic for time duration to recovery against change in voltage.Rectifier loads are particularly sensitive to voltage sags
19 DeRegulation & Generators Particular utilities have standard requirements (called grid codes) for generators before the generator can connect to the grid.However, between utilities there is, as yet, no consistency among the grid codes used.Once requirements in a utility are established they may be historical and may revolve around the weakest link in the utility system.This may cause problems for some units that may be required to conform to the weakest link grid codes. (Extreme frequency deviations, extreme VAR limits, etc.)
20 Resulting Problems Result is inconsistent standards in delivery May result in more expensive units to meet the codesIn some areas of operation can lead to extreme anomalies in operation, for example may never operate in the leading PF range.Difficulties in matching overall system requirements to generator capacity.Although the machines may be capable of producing the power they may be penalized for not operating in the extremes - hence leading to more expensive power.
21 New TechnologiesTo develop a rational maintenance schedule we need to make us of new technologies, for example monitoring partial discharges of the stator windings of generators.Some insulation materials have predictable partial discharge behaviour which may make it possible to determine the state of the winding, as well as the specific aging mechanism.By keeping a record of PD activity it is then possible to develop a rational maintenance schedule.This type of monitoring can be set up as an intelligent system to warn of impending winding failure.
23 From these plots we can determine: The overall degradation of the stator windingThe partial discharge activity: the maximum magnitude of pulses with a particular repetition rateThe trend of partial discharge activity which yields the progression of insulation agingAnalysis of the pulse phase plot can pinpoint the location of the activity - slot or endwindingPulse patterns reveal the nature of the partial discharge activity, including the predominant sources.
24 Winding Deterioration Factors Voltage switches and variationsOperating conditionsFluctuations in loadMean operating voltage levelWinding temperatureHumidityAgingWinding displacement in slot - fit
25 Web-Based Monitoring and Control The web presents an opportunity for system automation and control.For large deregulated systems information transfer plays a large part in determining success.This gives rise to the concept of an on-line System Control and Data Acquisition System (SCADA) .When combined with an interactive energy management system, we have an effective operating system over long distances and between systems.To take advantage of this possibility will require substantive changes in individual SCADAs, as well as a very cooperative approach to selecting standards
26 An ACSR Conductor54 aluminum conductors in three layers19 steel conductors, two layers over a single wire
27 COOLTEMPMHTEMRCPredicts conductor behaviour over the life time by introducing statistical distribution of system loads, ambient temperature, and rise of conductor surface over ambient
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