HISTORY OF METERS
An Electricity meter or energy meter is a device that measures the amount of Electric Energy consumed by a consumer.Electricity meters are typically calibrated in billing units, the most common one being the kilowatt hour [kWh].
1KWH or 1UNIT of energy is the amount of electric energy required to provide 1000 Watts of power for a period of one hour (eg.10 nos. of 100W incandescent bulb using energy for 1 hour)
The electric meters are installed near consumer premises to record energy consumed by them and billed periodically as per applicable prevailing tariff.
These are the I Generation Meters and are legacy meters of utilities. The most common type of electricity meter is the electromechanicalinduction watt-hour meter.The electromechanical induction meter operates by counting the revolutions of an aluminium disc which is made to rotate at a speed proportional to the power. The number of revolutions is thus proportional to the energy usage.
The accuracy of these meters are a cause of concern to the utilities due to mechanical moving parts associated with it and also due to ingress of dust and moisture over a period of time. As such CEA has issued guidelines to dispense with mechanical meters and switch over to high accuracy meters.
Electronic Meters are II Generation Meters.
Electronic watt-hour meters use solid state circuits to produce electrical signals whose frequency or strength is proportional to the volt and current being used. These signals are converted into energy measurements recorded by mechanical or electronic indicators. Electronic meters though are expensive to mechanical meters, are more accurate.
Electronic meters display the energy used on an LCD or LED display, and can also transmit readings to remote places. In addition to measuring energy used, electronic meters can also record other parameters of the load and supply such as maximum demand, Power Factor and Reactive Power used etc. They can also support time-of-day billing, for example, recording the amount of energy used during on-peak and off-peak hours.
Measures have been taken to replace all the Electromechanical Meters by Electrostatic Meters in BESCOM
Time of day metering
Time of Day metering (TOD), also known as Time of Usage (TOU) or Seasonal Time of Day (SToD), metering involves dividing the day, month and year into tariff slots and with higher rates at peak load periods and low tariff rates at off-peak load periods. While this can be used to automatically control usage on the part of the customer (resulting in automatic load control), it is often simply the customers responsibility to control his own usage, or pay accordingly (voluntary load control). This also allows the utilities to plan their transmission infrastructure appropriately.
Thus TOD is a Demand Side Management(DSM) initiative.
Further, as per the KERC order dated 30.04.2012, it is mandatory to make TOD tariff compulsory for all HT installations above 500KVA under HT2(a) & HT2(b) tariff w.e.f. 1st Sept 2012.