Cement, Energy and Environment

The concept of power conservation implies that the magnitude of avoidable energy loss in the power application areas is equivalent to extra generation of power. Action on elimination of this power loss means adding extra generation capacity to the system or saving this extra investment. It is with this spirit of commitment that an energy conservation drive is programmed. The area of conservation relates to the major users of electricity. Expansion of power generation capacity continues in the country, but the avoidable power leakage and losses should not be allowed to increase proportionately with the rise in capacity. Power demand increases with rise in population , industrialization and hike in standard of living. It means the extra generation is feeding the avoidable losses due to our inaction and thus our valuable resources are wasted to this extent. This title highlights some of the areas for acting on the control measures in this direction. Main divisions of the power system are generation, transmission, distribution and utilization of electrical energy. An analysis of the power system indicates that among others, distribution and utilization account for about 75% of the total cases of failures. At each of these stages energy leakage/loss occurs. Reduction and control of this loss in itself add to the generation capacity of the system. The aim of an efficient and effective system is to control the avoidable losses and optimize the load conditions of power demand. Hence, power generation should conform to the demand load and to the specifications laid down for the supply system. A departure from these parameters can cause energy losses. Power Quality At the power generation stage, it is important to focus on the quality of power. It is described by the following parameters under the international IEC standard. o Voltage o Power factor o Frequency o Harmonic distortion Voltage: Under the situation in India, the prevailing voltage variations in the power supply system are caused by the transmission and distribution of power; whereas, within a network, these variations are produced by the connected load characteristics i.e. reactance. Voltage drop means more current flowing and consequently higher copper losses (IR losses) of the network. For example, a 20 % voltage drop amounts to 56 % losses. Hence the supply voltage variation should not exceed 4- 5%. It should be closely maintained in accordance to the recommended voltage marked on the nameplate of the motor. Voltage variation within phases should be controlled to 1%. Phase imbalances must be regulated within tolerance limits; otherwise, it gives rise to winding temperature. Power factor: It is the ratio of active energy to apparent energy. Ideal power factor is unity. Lower power factor means higher energy consumption and is followed by a voltage drop indicating the nature of connected load. Power factor should be maintained as high as possible. Use of capacitor bank is advisable for improving the same. Capacitor should have low losses, long life, high over– current capability and improved heat dissipation feature. Frequency: It is caused by the fluctuations in the load level of the supply system. A heavily loaded system will reduce the frequency of the power supply. It adversely affects the system parameters. It calls for a control on the power supply system. Harmonic Distortion: Non– linear load causes harmonic currents. It is like polluting the network or pollution of the grid produced by an unscrupulous consumer. Harmonic distortion impacts higher energy consumption of the connected load. Electrical equipments like transformers, motors etc. record higher iron and copper losses in proportion to the power of the . lh 7 th h . frequency 1.e. 5 , armomc and so on. Higher temperature in the core promotes fast aging of the protective insulation ending in premature failure of the equipment. Harmonic distortions can cause rise in motor temperature. Electric Motors Electric motors, in a way are the largest consumers of electricity. Power to the motor is made up of two components; one is the effective and useful net power that is available for the process and the other component of power accounts for the losses (iron and copper) as a result of conversion from electrical input to mechanical output. It is observed that single– phase fractional horsepower and 3-phase induction motors are widely used in industry, which are designed to run at constant speed . They constitute a 29