Distribution reforms and metering

By S. K. Singhvi

The problem

The vertically integrated State Electricity Boards were created for generation, transmission, and distribution of electricity as per the provision of the Indian Electricity Act. This structure has yielded reasonable results with respect to rural electrification but the supply of power below the cost of supply to various categories of consumers resulted in the bankruptcy of almost all the electricity boards in the country.

For the commercial viability and success of the deregulation, it is essential to examine the main causes of the present situation of the State Electricity Boards.

Some of them are:

  • Inadequate energy accounting (balancing and energy audit).
  • Long cash-flow cycle.
  • Irrational tariff structure.
  • Poor maintenance/utilisation of system assets, including metering system,
  • Inadequate revenue protection
  • Non-collection of dues.

The success of deregulation will depend on how effectively transmission and distribution utilities address these issues. This paper suggests some of the actions for the deregulated utilities to address these issues through proper metering, billing, and software tools.

Energy Balancing

The T&D losses have traditionally been under-reported to about 20-22%, Restructuring has brought about better visibility of actual losses. The losses reported post-restructuring are about 40-45%. Accounting adjustments under the agricultural and other heads are difficult in the new regime. In order to ascertain the correct tariff, various Regulatory Commissions are now insisting on proper energy accounting. To put the T&D losses in international perspective one may look at the limits of technical losses at various levels of transmission/distribution system worked out by EPRI of USA:

“To Manage anything One must measure it first.”

It is important to use proper technology for assessment/calculation of the losses at different voltage levels.. Traditionally the method of energy accounting/auditing was limited to taking reading of the metering equipment installed in the substations and comparing these readings with the revenue collected. Most of the meters were poor quality electromechanical and therefore, inaccurate. Time based measurement is critical for energy balance and loss assessment, this is possible with the electronic metering devices.

Loss Calculation in EHV Transmission System

The assessment of technical losses in the EHV transmission system needs an expertise/precision measurement system. The losses are around 0.5 – 1%. It is important to have a metering system of 0.2 class accuracy, with instrument transformer error compensation. Similarly, the loss at the intermediate voltage level and sub-transmission level are of the order of 1.5 to 3%. Even at the intermediate voltage level, it is essential to put energy meters of 0.2 class for proper accounting In all cases, the metering has to be done on a common time base for energy balance and accounting.

Energy Accounting in the Distribution System

This segment has the highest loss and therefore a proper energy accounting system is essential. One needs to remember that the Percentage loss in the distribution system is high as compared to the transmission system.

The investment required for the reduction of distribution losses is less compared to the loss reduction required in transmission system.

The distribution system in India has been operating in the past with inadequate metering. Majority of meters were either defective or inaccurate and, therefore, it was not possible to carry out energy auditing. The Government of India has taken initiative for 100% metering of 11 KV feeders and for the distribution transformers. Accurate energy metering is the cornerstone for The 11 KV feeders and end-consumer premises metering is fundamental. However, energy meters alone shall not guarantee an assessment of the loss reliably. The utilities need to have proper drawing/data to link consumers to specific distribution transformers, data of distribution transformers, in turn, need be linked to the consumers’ billing data. It will be difficult to envisage a system relying on regular energy meter readings of tens of thousands of distribution transformers and compare it with the billing data without the help of proper IT and organisational infrastructure. We need to look into the investment in the distribution transformer metering. Technologically it is now possible to identify the consumers to a particular distribution transformer.

Another method of energy auditing in the distribution system is state estimation technology. The state estimation is a process of assigning a value to an unknown system state variable based on measurements taken from the field. The additional errors introduced while applying the state estimation technique are at best a small percentage value of the quantity that is required to be measured. There are many techniques and methods for state estimation and these techniques have been used for power system stability and contingency analysis. Now, this technology is available for distribution loss assessment.

“Technical solutions are now possible to reduce the billing cycle and bad debts”.

Billing cycle

The cash-flow cycle of the utility is interlinked with the billing cycle. The billing cycle involves:

  • Data collection from each of the meters installed at the consumer premises.
  • Transfer/Transcribe the collected data on to a computer.
  • Validation of the entered data.
  • Bill printing.
  • Sending a bill to the consumer.
  • Revenue collection.

The whole billing cycle takes about 15 days to 2 months depending upon the consumer category. This adversely affects the cash flow of the utilities. This system also increases the bad debts of the utility, as a large percentage of consumers choose not to pay even after the receipt of the bills. Technical solutions are now possible for the reduction of the billing cycle and bad debts. Technology can be used for various categories of consumers to reduce the billing cycle.

1. HT Consumers

Automatic meter reading is an appropriate technology for High Tension(HT) consumers. High revenue being collected from this category of consumers makes the investment decision very simple. It is possible to read all the meters from the utility billing centre directly using the various communication links such as PSTN, GSM etc. The meter reading can directly be linked to utility billing software and therefore, the billing cycle can be reduced drastically. In addition to the reduction in the billing cycle, this also helps in monitoring of the consumers and, therefore, tamper and fraud are minimised. Data transfer errors are eliminated.

2. LT Industrial Consumers

Billing cycle for consumers in this category can be shortened by electronic reading of the meters. Special software on portable hand-held terminals guide the meter reader through the proposed route. The readings can be taken electronically and the data can be directly linked to the utility computer and the bills can be generated on the same day. It is also possible to generate bills at site using reliable portable printer.

Software on the HHU allows entry of abnormal conditions at site such as broken meter seal, broken meter cover etc. It is possible to analyse consumption pattern of various customers and discrepancy reports can be generated where consumption pattern is abnormal.

3. Commercial/Domestic Consumers

Prepayment metering solution for this category of consumers can be effectively implemented for reducing the billing cycle. Here the consumers have to pay in advance before he actually consumes the energy and therefore chances of bad debts are eliminated. Prepayment metering system has the following additional benefits:-
a) No meter reading and hence lower overheads.
b) DSM/Load management
c) No billing errors
d) Improved budgeting for customers
e) Increased customer confidence.

Various methods of vending electricity can be used. This technology is being widely used in Europe, Africa, and other countries and is now commercially available in India. A proper legal framework for the implementation of this technology needs to be created. The prepayment metering system provides an advance warning to the consumers. In the proposed Electricity Bill 2001 the consumers can take supply through prepayment metering and the distribution licensee shall not be entitled to required security as per Section 48 (5A) However, the Clause 57(1) still require utility to give 7 days notice in writing to the consumers before the supply is disconnected. This will create bottlenecks in implementing prepayment metering and, therefore, the Government of India needs to make appropriate provisions in the Electricity Bill. Warning on the display of a prepayment meter can be accepted as compliance with the provisions of the Electricity Act. In order to encourage residential consumers to use prepayment technology, the State Regulators should think of offering incentives to the commercial/ domestic consumers. The success of Prepaid mobile telephones shows the mass acceptance of the concept of budgeting the expenses. Another important area where the utilities need to focus on is the availability of the power supply.

There are frequent power cuts, especially in the semi-urban and rural areas. Various feeders are disconnected on a rotational basis in accordance with the available supply. It is advisable that rather than disconnecting the whole feeder, utilities install a metering system that has load limiting features. During peak hours meters can be programmed to supply restricted load to such that the consumers at least get power for their lighting and essential loads. This will meet the consumer expectation for the availability of power supply and at the same time the restricted demand imposed on the distribution system.

Usage of metering system

Massive numbers of energy meters are being installed by utilities around the country. For proper utilisation of this investment, the following issues need to be looked into:
a) Lack of IT infrastructure
b) Organisational issues
c) Regulatory issues
d) Standards/Specifications
e) Legal metrology

a) Lack of IT infrastructure:
The IT infrastructure needs to be adequate to cater to the demands of the growing metering and billing system. Microprocessor-based energy meters record useful information such as load profiles, tamper information, billing history but field staff needs to have proper tools and skills to analyse the available data. Load surveys and tamper information once analysed with proper software can be used as a very effective tool for revenue protection. Load survey data can also be used for load forecasting, tariff planning, etc.

b) Organisational issues:
(i) Metering & revenue protection teams: Utilities need to create a special cadre of metering and revenue protection personnel. These teams can be tasked to look after both technical and commercial aspects of metering. Training of field staff is an important issue. Utility engineers at the corporate level working in procurement/planning/system design are quite familiar with different functions of meters but this knowledge is inadequate at field level. Utilities and industry can work together to achieve this objective so that full benefit out of meters packed with features can be derived.

(ii) Application Engineering: It is essential to select the right kind of meter for different applications. Metering needs to be integrated with the right communication technology. Overall metering accuracy including that of instrument transformers is important. Instrument transformers rated burden should match with meter burden to get better overall metering accuracy. Utilities, therefore, need to create more organisational focus on the application of the metering system.

c) Regulatory issues:
Regulators will demand detailed information for tariff finalisation, and rightly so. Utilities need to examine whether the metering scheme being implemented by them will meet the expectations of consumers/regulators.

d) Standards/specification issues:
Testing links: Voltage links are designed into meters for the sole purpose of testing the meters in the laboratory. A meter spends no more than one hour or 0.0004% of its use in the lab, the other 131,400 hours are spent on the circuit. With electronic meters, utility test labs add little value because these devices cannot be adjusted. The terminal block links provide easy tamper access during the 99.9996% of the time spent on the circuit.
Meter tampering: Metering standards /specifications define a certain level of external influence. What about influences beyond these levels? Standards should now recommend meters that discourage consumers from tampering. Meter can be designed so that they record at a maximum consumption level when attempts are made to tamper.

e) Legal metrology
Presently there is no system of certification of the installed base of meters in our country. We need to formulate some system where the installed base of meters, including domestic meters, is certified in the field itself based on the guidelines to be fixed by the regulatory bodies. We also need to have a proper monitoring system for the satisfactory performance of the installed base of meters. This also plays a very important role in revenue management.

Revenue protection

Utilities need to review their meter installation practices, as it plays a very important role in revenue protection.

 

Installation practices:

a) Connection check: Although it appears a very simple job in many high tension and low tension CT operated metering installations, loss of revenue has been reported due to the wrong connection. Static energy meters can assist utility engineers in wiring correctly . Microprocessor-based energy meters communicate information on specific electrical quantities. The use of software simplifies the job of installing meters correctly and eliminates errors.

b) Meter enclosures: The most common way of tampering with conventional electromechanical meters were either interfering with moving discs or fiddling with the wiring. Microprocessor-based energy meters do not have any moving parts and also detect fiddling with wires. Electricity Mafia now is moving towards vandalism i.e. trying to physically damage meters. Meters can be protected from such vandalism if quality meter boxes are used.

c) Meter sealing: Meter sealing Practices need to be reviewed. A lot of innovation has taken place in the technology of Seals. Good quality plastic seals made of polycarbonate and numbers marked on them with laser technology are available.

Conclusion

It can be concluded that technologies have been and are available within the country for computation of technical and non-technical losses and identifying areas of high losses. Utilities need to implement such technological solutions so that a measure of the problem and effectivity of proposed solutions is available. Like all other businesses Utilities need to focus on their cash-flow cycle. Technical solutions such as prepayment metering, remote metering, etc. which can considerably reduce the billing
cycle needs to be implemented.

The revenue protection including installation and usage of electronic metering systems also needs to be reviewed.