[b]Please give about micro controller based automatic load shedding in this blank [/b]
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An energy system is functioning normally the amount of electrical energy generated is the amount of electrical energy consumed. The load on the system is greater than the generation, the load shedding is deciding to maintain the system frequency. As soon as the load on the generator increases, there will be a system drop frequency and the rate drop rate is the determining factor for the amount of load to be released. The amount of load shedding must be minimal necessary to recover the system frequency, but should be sufficient to cancel the generation deficit. Due to the advancement in computer technology microcontrollers are widely used for on-line instrumentation, control and projection. The microcontroller scheme is fast, accurate, reliable and eliminates the use of a large number of measuring instruments and relays. A microcontroller scheme has been developed for load shedding based on the rate of frequency drop. This load shedding is basically composed of two secondary schemes as follows. The first scheme is for a wave situation there is sufficient generation capacity but there is a frequency drop over a short period due to a sudden switching of heavy load in the system. Load shedding is required to stop the highest rate of fall of frequency only, as soon as the generation improves or the response of the mechanical governor to the demand increase the loads are restored the second scheme is for a situation where the demand is more Than the generating capacity of the system. The load shedding is required as soon as the demand becomes greater than the generating capacity of the power system. Therefore the unimportant load is shed one by one by disconnecting feeders until the frequency returns to normal. If the generation capacity remains less than the demand for a longer period, the power is distributed in different centers of load in rotation. The first scheme as soon as a frequency drop occurs the microcontroller measures the rate of frequency drop. Depending on the measured value of df / dt, the microcontroller decides the frequency at which the system will fall due to the time delay that disconnects the load and that corresponds to the previous calculated frequency the total amount of load to be shredded. The load shedding of the decision feeders is performed accordingly. Then check the capacity of generating the power of the load. The power supply is smaller than the nominal output of the generator, the microcontroller sends signals to the operator or governor to increase the input and the load is restored one by one as soon as the frequency goes from 50 Hz. The second scheme was the load shedding of minor loads which is performed on the basis of the frequency drop rate. Then the different load centers receive power in rotation or in the order of difference. As soon as the generation is generated or the peak charge period is over the energy is restored to the load centers. We will focus only on the second scheme for our future analysis.
Block diagram