14-11-2012, 02:36 PM
Fighting Electricity Theft with Advanced Metering Infrastructure
energy-fighting-electricity-theft-with-advanced-metering-infrastructure.pdf (Size: 633.07 KB / Downloads: 139)
Introduction
All over the world, utilities are experiencing significant revenue losses due to
non-technical reasons. These losses are mainly caused by electricity theft and
unpaid bills. Because of political, sociological, and cultural reasons, it is, in many
cases, difficult to fight these phenomena. Advanced Metering Infrastructure (AMI)
provides technical tools that minimize these losses. AMI can provide meter
readings that are difficult to manipulate with inherent theft and fraud detection
mechanisms, including tampering detection, theft calculation, and alarms. By
adding AMI services like prepaid billing, the technology also resolves the problem
of unpaid bills.
In this paper we describe the capabilities of AMI to reduce revenue losses due to
non-technical reasons.
Electricity Theft
Revenue losses caused by electricity theft affect the quality of supply, the electrical
load on the generating station, and the tariff imposed on usage by genuine
customers.
This paper discusses various new methods offered by the novel AMI to detect,
locate, quantify, and control incidences of theft.
Methods of Preventing Fraud
The most common form of theft is tapping electricity directly from the distribution
feeder and tampering with the energy meter.
AMI presents a variety of methods that detect, locate, quantify, and control
electricity theft. The techniques include:
Modern smart meters
Preplanned smart meter installation topology
Analysis of smart meter readings to identify theft profiles
A managed prepaid billing service
Smart Meter-based Techniques
Resolving Theft via Mechanical Meters
Tampering with the legacy mechanical energy meters is aimed to stop/slow the
rotation of the meter or to give a lower reading.
By simply replacing the existing electromagnetic (rotating disk) meters, we can
resolve a variety of theft methods designed to distort the meter reading. These
methods include:
Inserting a film or depositing a highly viscous fluid.
Using strong magnets like neodymium magnets to interrupt the rotation of the
disk.
Modern smart meters are immune to these methods since they do not have any
rotating parts and the metering circuits are protected against external magnets.
Preplanned Installation Topology of Smart Meters
Illegal consumption of electricity can be discovered by using a remote check meter
that detects and measures the quantity of electricity lost. Measuring consumer data
at regular intervals may initiate sending vigilance officials to inspect illegal
consumer installations.
Using the existing smart meters as a building block, we can build an AMI topology
that implements two main methods of detecting power theft:
1. Detecting unmetered consumption
2. Detecting excessive load
Detecting Unmetered Consumption
The unmetered consumption detection method comprises installing a utility AMI
with a tree of meters so that a meter closer to the root measures the power
consumed by the loads below it. By placing a “sum meter” at a node of the
residential power grid and additional meters below it that measure the consumption
of branches or specific loads in the tree below, the system performs a comparison
between the sum meter and the branch/load meters sum. If the sum meter
measurement is greater than the sum of the downstream meters measurements, it is
a strong indication of an illegal load that consumes power.
Unpaid Bills
The Managed Prepaid Billing Service
The phenomenon of unpaid bills is another major reason for power utilities’
revenue loss.
While current prepaid billing meters use some kind of physical token (coin, scratch
card, etc.), smart meters offer a “virtualization” capability so that users can
“purchase electricity” without using a tangible object.
By deploying a friendly, smart, meter-based prepaid billing service, customers
become accustomed to paying for electricity when they need it, relieving the utility
of having to make the consumer pay for electricity already used (as in the post-paid
service).
Several studies have already demonstrated that prepaid billing results in
considerable energy conservation by the user (in the USA, a 4-12 percent saving
has been measured).
For AMI, prepaid billing is just an additional service. AMI runs on specific SW
that is remotely controlled to allow electricity usage from a control center. There is
no need for an additional metering infrastructure and expensive meters (capable of,
for example, receiving coins or smart card numbers).
Since the prepaid service is controlled remotely, it may have features that allow
customers to request grace periods in case of emergency, thus reducing the “social”
problems of prepaid billing.