Know your meter

Not a stranger, but while treated most of the times even worse than a stranger, the billing officer is used to visit our places once a month. It’s most of the times antagonizing to see a substantial amount written on the bill, especially when we feel that we didn’t consume THAT MUCH !! But the problem is how we identify THAT MUCH quantity?

The small device the billing officer looking at, while pressing the buttons of his calculator and taking down notes, is colloquially known as the “Meter”. But ideally, it should be the Domestic Electrical Energy Meter. However, the electricity bill itself refers to this device as the “Meter” (Doubt me? Just have a glance at the electricity bill of the last month), authenticating the use of that simple singular word, instead of a complex tech jargon. Domestic Electrical Energy Meter is capable of measuring the total power consumed passed through it. The electrical supply to the house passes the meter, recording those quanta of power is consumed.

The theory behind the energy meter is what we learned in the secondary school. Power consumed by any electrical device is simply equal to the value of the voltage times the current. However, in a broader analysis, domestic electrical energy meter measures only the active power consumed by the equipment. The reactive power consumed is ignored in domestic measurements of power. But in industrial applications, demand meters are used to measure the maximum apparent power consumed, which is the vector sum of active and reactive powers.

Getting back to the domestic meter, the old fashioned meters have two coils, namely the voltage coil and the current coil, and a rotating disc. The interaction of flux generated by the two coils induces eddy currents on the disc. These eddy currents react with the magnetic flux and exert a rotating torque on the metallic disc. Now I know you doubt why this disk is not accelerating because of the torque, which should be the normal behavior. The disk is damped using a permanent magnet to deliver a reverse torque. This balances the torque and cause the meter to rotate in a constant speed, which is directly proportional to the electrical energy passed through. The spinning dials rotate accordingly to record the number of turns the disk is rotated, which is the indication for the consumption of power.

The digital energy meters replaced the demand to those mechanical meters, with sophisticated electronic components integrated into a smaller volume. Evolvements of meters in terms of technology is significant, and now we see smart meters which are capable of communicating with remote sources through GPRS or other similar telecommunication methods , to transfer energy data. All the meters imported are tested on a sample basis at the meter testing lab at Ja-Ela, owned by Lanka Electricity Company Limited.

Knowing all about meters will not help your pocket by any means, unless you understand the tariff structure. It is worth for any consumer to have an understanding about the tariff structure for the domestic customers.

The process of calculating the energy charge is simple. The meter reading depicts how many units the consumer has used.Domestic tariff is a block tariff and the table shows the tariff structure for a 30 day billing period. Billing period is the number of days from the previous billing date to the current billing date. The size of the block depends on the billing period. For example if the billing period is 32 days, the first block will be 0-32 kWh and the 5th block will be 129-192 kWh. Based on the interval to which the last unit is falling to, the fixed charge is decided. This prevent the customer from moving into a higher fixed charge, because of the delay of billing officers visit. Number of units used in each interval is multiplied by the respective energy charge and added together to form up the total energy charge. The fuel adjustment charge is a percentage of energy charge, calculated according to the table below. More details on this calculation process will be available in the next article on metering.

At a glance it is noted that both the fixed charge and the energy charge per kilo watt hour jumps up abruptly at the 90 unit margin. Therefore, if you are mindful to manage your consumption below 90 units, that will be at your advantage. Try the bill calculator in EnergyzEE blog, you will be able to calculate your own bill in a split second. Tricks to save the bill is yet to come with Energy zEE

Electricity Bill Calculator by EnergyzEE

Article By: Pasan Pethiyagoda

Posted in: Utility and Social