Electricity Leakage: Types and Control Measures

Kathmandu; Under the informative column "Urja Gyan" every Friday by Urja Khabar, this week we share with you knowledge about electricity leakage. Last week we covered topics concerning the electricity distribution system and distribution lines.

1. What is Electricity Leakage?

Simply put, electricity leakage is the difference between the electricity units generated by a power plant and the units consumed by customers. For example, when 100 units of electricity are generated by a generating plant but the consumers consume only 80 units, the leakage is 100 - 80 = 20 units. The leakage occurs in the transmission and distribution system from the generating point to the house of the consumer.

Nowadays, energy meters are installed on substations that feed 11 kV or 33 kV lines to towns and villages. These meters record the amount of electricity passing through the line.

For instance, if an energy meter on a substation reads 10,000 units, and the overall consumption recorded in industries and homes connected on that line is 8,500 units, then the leakage is: 10,000 - 8,500 = 1,500 units. This leakage occurs in the distribution process from the substation to the consumer's homes.

2. Types of Electricity Leakage

Electricity leakage is detrimental to producers, distributors, and consumers. Electricity leakage is classified into two types:

(A) Technical Losses (TL) : Technical losses occur due to the absorption of energy by conductors as electricity flows through them. Some of the common causes of technical losses are:

• Low voltage in homes
• Voltage drop leading to inefficiency
• Power dissipation in electrical lines

Techniques for Reducing Technical Losses:

• Using thicker conductors: Thinner conductors increase the amount of resistance and thus losses. The use of an appropriate thickness of the conductor based on the load can reduce losses.
• Placing transformers at load centers: Transformers should be located close to the center of a locality or village rather than at a corner to reduce losses.
• Load balancing: The R, Y, and B phases of a transformer should be loaded equally. Uneven loading causes more current to flow through the neutral wire, increasing losses.
• Using smaller transformers where required: Where there are fewer houses and low consumption, 10 kVA or 15 kVA transformers should be used instead of long low-voltage (LT) lines.
• Installation of capacitors: Due to low power factor, more current flows through the lines and therefore the losses are higher. Power factor is enhanced and technical losses are lower with capacitor installation.
• High-quality transformers: Transformers that are built using high-grade silicon steel core conserve energy loss. Though expensive, these are more efficient.

(B) Non-Technical Losses (NTL) : Non-technical losses happen due to meter tampering, meter bypassing, and theft of electricity. Some of the prevalent illicit practices are:

• Breaking meter seals and interfering with internal mechanisms to retard readings
• Bypassing meters by connecting wires directly to the main supply
• Utilizing hooks (illegal connections) to steal power
• These are criminal acts and are punishable.

Multiple-Choice Questions (MCQs)

1. What is the name of the cable that goes from the pole to the house meter?

(A) Service Cable
(B) Naked Cable
(C) Overhead Cable
(D) Power Cable

✔ Answer: (A) Service Cable

2. What is the lowest wire in a 400V distribution system named?

(A) R Phase
(B) Y Phase
(C) Neutral
(D) B Phase

✔ (C) Neutral

3. How many and which type of switches are required to operate a bulb from two points?

(A) Single-way – Two switches
(B) Single-way and Two-way – Two switches
(C) Two-way – One switch
(D) Two-way – Two switches

✔ (D) Two-way – Two switches

4. What decides the depth at which an electric pole is to be buried?

(A) Pole thickness
(B) Pole length
(C) Both pole length and thickness
(D) None of the above

✔ (C) Both pole length and thickness

5. What type of insulator is most widely employed in a 230/380V distribution line?

(A) Pin Insulator
(B) Shackle Insulator
(C) Disc Insulator
(D) Stay Insulator

✔ (B) Shackle Insulator

6. Which voltage level is NOT employed in Nepal's transmission and distribution system?

(A) 110 kV
(B) 11 kV
(C) 33 kV
(D) 66 kV

✔ (A) 110 kV

7. What type of distribution system is employed in a residential area?

(A) Single Phase
(B) Three-phase, Three-wire
(C) Three-phase, Four-wire
(D) None of the above

✔ (C) Three-phase, Four-wire