Tarrif and load curves
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This document discusses different aspects of tariffs for electricity supply including objectives, types of tariffs, and key terms. It describes five main types of tariffs - simple, flat rate, block rate, two part, and maximum demand tariffs. It also covers related concepts like connected load, maximum demand, demand factor, diversity factor, load factor, reserves, load curves, and load duration curves.
Tarrif and load curves
- 1. Gujarat Power Engineering & Research Institute By- -Ishani Bhatt(03) -Vibha Patel(44) -Karan Thawani(58) -Madhav Rami(50) Contents:- -Tariff -Economic Aspects -Reserves -Load and Load duration curves
- 2. oThe electrical energy produced at the generating station is delivered to a large number of consumers. o The rate at which energy is sold to the consumers is called “TARIFF.” oPricing the electricity generated is a truly complex issue. Because a lot of costs are involved in producing a unit of electricity from the coal in generation stations to transmission lines losses to distribution system losses and metering errors. General form of tariffs: akWh + bkW+ c
- 3. OBJECTIVES OF TARIFF (1) Recovery of cost of electrical energy generated at the generating system. (2) Recovery of cost on the capital investment in transmission and distribution system. (3) Recovery of cost of operation, supplies and maintenance of equipment. (4) Recovery of cost of metering equipment, billing and miscellaneous services . (5) A marginal return (Profit) on the capital investment .
- 4. TYPES OF TARIFF Types • SimpleTariff • Flat RateTariff Types • Block RateTariff • Two PartTariff Types • Maximum DemandTariff • Power FactorTariff
- 5. (1) Simple Tariff: The tariff in which the rate per unit of energy is fixed, is called simple tariff. o It is in simplest form and easily understood by the consumers. o Consumer is to pay as per his consumption. ADVANTAGES General form : akWh
- 6. (2) FLAT RATE TARIFF: The tariff in which different types of consumers are charged at different per unit rates is called flat rate tariff. ADVANTAGES oIt is more fair to different types of consumers. oIt is quite simple in calculations. General form : akWh
- 7. (3) BLOCK RATE TARIFF: Different blocks of energy consumption are charged at different rates. o For example, for the first 50 units the charge will be Rs. 1.85 per unit and for the next 50 units the charge is Rs.2.90 per unit.
- 8. (4) TWO PART TARIFF: Apart from the energy consumed, there is charge for the maximum demand also. Total charges= Rs. (a X kW + b X kWh ) where, Rs. a= charges per kW of maximum demand Rs. b= charges per kWh of energy consumed
- 9. (5)MAXIMUM DEMAND TARIFF: The tariff in which electrical energy is charged on the basis of maximum demand of the consumer. (6) POWER FACTOR TARIFF: Power factor tariffs are devised to differentiate between the good power factor users and poor power factor users. (a) KVA MAXIMUM DEMAND TARIFF: Instead of charging the maximum real power demand, maximum kVA demand is charged in addition to the charge corresponding to energy.
- 10. (b)KWH AND KVARH TARIFF: Both kWh and kVAh (the reactive power consumption are charged separately. (c) SLIDING SCALE TARIFF:There is some extra charge if the power factor is below the set value (0.8). If consumers improve the power factor an incentive will be given to those consumers.
- 11. CONNECTED LOAD: Sum of the continuous rating of the entire load consuming apparatus connected to the system. MAXIMUM DEMAND : The maximum demand of an installation or system is the greatest of all the demands that have occurred during a given period . DEMAND FACTOR : This is the ratio of the peak demand to the connected load. oThis can be less than or equal to one. Demand Factor Load Maximum Demand Connected
- 12. DIVERSITY FACTOR: It is the ratio of sum of individual maximum demand to the maximum demand of the whole power system. o It is always greater than one LOAD FACTOR: Load factor determines the capability of load utilization i.e. how long it is utilizing the power. oThe load factor for a load is high if it switched on for most of the time and is less when it is off for most of the time. Of Individual Demand Factor= Demand Of Entire Group Sum Maximum Diversity Maximum
- 13. oThe definition goes like this : it is the ratio of average load to the maximum load. oAlthough this is not the exact definition. The exact definition is the ratio of energy consumed to maximum energy it can consume. oA consumer is always defined by his load factor. oWhenever a power plant is constructed it is designed to serve the maximum demand of the customers Load Load Factor= Load Average Maximum
- 14. PLANT CAPACITY FACTOR: It is defined as the ratio of actual energy produced in kilowatt hours (kWh) to the maximum possible energy that could have been produced during the same period. where, E = Energy produced (kWh) in a given period, C = Capacity of the plant in kW, and t = Total number of hours in the given period. Plant Capacity Factor= E C t
- 15. PLANT USE FACTOR: It is defined as the ratio of energy produced in a given time to the maximum possible energy that could have been produced during the actual number of hours the plant was in operation. where, E = Energy produced (kWh) in a given period, C = Capacity of the plant in kW, and t1= Actual number of hours the plant has been operation. Plant Use Factor= 1 E C t
- 16. RESERVES SPINNING RESERVE: It is the generating capacity which is connected to a bus (common connection) and is ready to take the load. COLD RESERVE: It is that reserve generating capacity which is available for service but not in operation. HOT RESERVE: It is that reserve generating capacity which is in operation but not in service.
- 17. FIRM POWER: It is the power intended to be always available (even under emergency condition). RESERVE MARGIN: It is the difference between the rated capacity and the actual loading on the generator.
- 18. oA load curve (or load graph) is a graphic record showing the power demands for every instant during a certain time interval. oSuch a record may cover 1 hour, in which case it would be an hourly load graph; 24 hours, in which case it would be a daily load graph; a month in which case it would be a monthly load graph; or a year (7860 hours), in which case it would be a yearly load graph. LOAD CURVES
- 20. -The following points are worth noting : (i) The area under the load curve represents the energy generated in the period considered. (ii) The area under the curve divided by the total number of hours gives the average load on the power station. (iii) The peak load indicated by the load curve/graph represents the maximum demand of the power station.
- 21. LOAD DURATION CURVES: oAll the loads are rearranged in descending order. Time(Hours) Load(kW) Base Load Peak Load
- 22. The following points are worth noting : oThe area under the load duration curve represents total energy delivered by the generating station. oProper selection of base load power plants and peak load power plants becomes easier.