Presently consumers are using different methods to tamper the energy meter. There have been numerous new techniques emerging for tampering of meters. In order to prevent theft, to make the meter more resistant to theft, and to make the meter smart enough to detect theft, utilities are continually improving their specifications for meters. The utilities have implemented a number of cutting-edge measures to reduce electricity fraud and theft. The addition of anti-tamper features to energy meters is one way to lower the incidence of energy theft, reduce the frequency of energy theft, or stop meter tampering. Present days meters have antitamper features to identify the theft and log the tamper with date and time stamping. Meter can keep a record of large nos. of tampers, normally 200 tampers in three phase meter and 100 tampers in single phase meter. Meters are also programmed to record the energy at their maximum current rating under certain tamper condition to penalise the consumer or to discourage the consumer from attempting the theft.
Further technological advancement is two-way communication and introduction of Load switch in Smart Meters, assist the utility in identifying the meter tampering and to take the action immediately.
Every 10 or 15 minutes, smart metres communicate with the Data Concentrator Unit (DCU) to record and report all the parameters, including the detection of theft.
Information from Smart Meter goes to Data Concentrator Unit (DCU) when meter records any tamper event and then it goes to Head End System (HES) and finally the utility can decide whether to disconnect the consumers load through load switch of Smart meters. With the use of this technology, utilities may now identify dishonest customers and penalise them based on metering information kept in the Energy meter’s memory.
Events condition and table as per standard
A tamper event in the meter occurs when it is subjected to any abnormal operating condition or any condition that is not standard operating condition of the meter. The meter shall record all the occurrence time and restoration time of all such events must be stored in the meter. There are lists of parameters declared as per Indian standard, which must be recorded along with date and time of the events.
Tamper and other relevant events are given in the Indian standard – IS 15959 (Part 1& 2) Whole Current meters and IS15959 (Part 3) for Current & Voltage Transformer operated meters. Total number of events store in the meter depends upon requirement of utilities. Indian standard said to store minimum two hundred numbers of such events. Any abnormal condition that forces a meter to create fraud/tamper is considered as an Tamper Event and stored in an Event Object code (OBIS = 0.0.96.11.e.255 IC = 1) where value of “e” ranging between 0 & 6. All the tamper events are divided in the seven different groups. This grouping of events depends upon their nature of occurrence. The various event categories are given below.
Voltage related event
These Events primarily depend on supply voltage. There are total twelve events in this category. All the twelve events are applicable only to three phase smart meters. For single phase smart meter, only over voltage and low voltage event are applicable. All the twelve events are given in the table1. These events are stored in Object 0.0.99.98.0.255 in the Interface class 7 as a profile generic object.
Current related event
Current related events primarily depend upon the load conditions. There are total twenty events in this category. For three phase meter all events are applicable as per table 2 except Earth Loading Event. For single phase event only current reversal and earth loading events are applicable. These events are stored in Object 0.0.99.98.1.255 in the Interface class 7 as a profile generic object.
Power related event
This event is dependent upon failure of power supply. Power failure event is applicable to all the categories of the meter. These events are stored in Object 0.0.99.98.2.255 in the Interface class 7 as a profile generic object.
Transaction related event
Transaction related events are generated within a smart meter when any configuration change occurs within the smart meter. All of the events in table 4 apply to direct connected meters that are single phase or three phase. For transformer operated meters, all the events are applicable except load limit set and load limit enable disable. RS 485 address event is applicable only to the meter having RS485 Communication port. The only smart meters that have RS485 communication port, RS485 addresses change event apply. These events are stored in Object 0.0.99.98.3.255 in the Interface class 7 as a profile generic object.
Other events
Other events primarily depend on the external abnormalities affecting the meter such as magnetic influence, removal or disturbance of neutral terminal of the meter etc. All the other events are given in the table 5. All the events in the table 5 are applicable to the single phase meter except low power factor events. For three phase meters all the events of table 5 are applicable. These events are stored in Object 0.0.99.98.4.255 in the Interface class 7 as a profile generic object.
Control events
Control events depend upon the operation of the load switch of the meter. Control events apply only to directly connected smart meters, both single & three phase meters and prepayment meters. Due to the lack of a load switch, these events are not applicable to smart meters connected through measuring transformers.
Non roll over events
Non roll over events, as name suggests, cannot be rolled over i.e., once this event occurs it cannot be restored. Only event that come in this category is meter cover open event. These events are stored in Object 0.0.99.98.6.255 in the Interface class 7 as a profile generic object.
Event push mechanism
Smart metres have the ability to transfer data and notify tamper events to the head end system in an unprompted manner, which is without receiving a request. The DLMS/COSEM already defines this as the “PUSH service. Some triggers are there to produce these push services. In the case of periodic push, triggers are meters real-time clocks i.e., as per the time scheduled in the meters. The event’s occurrence time recorded by meter serves as the trigger in the case of an event push. Utilising the PUSH service interface class (IC 40), the PUSH service is modelled in the smart meter. The table 8 lists all of the push services that apply to smart metres.
Conclusion
The major problem for power distribution companies in India is theft of electricity. Theft causes loss in terms of revenue. To control revenue losses, utility companies worldwide need to detect meter tampering and ensure accurate billing even if energy meters are tampered. Manipulation can range from simple techniques such as tampering with live or neutral wires to more sophisticated techniques such as hacking firmware and tampering with energy usage records.
Smart meters are capable of dealing with a very wide range of tampers and abnormal conditions. Special care need to be taken for filtering out the intentional fraud and temporary conditions, which are caused due to system conditions. Push mechanism in smart meters are designed for the detection and early removal of tamper by disconnecting the load through disconnection mechanism of the smart meters. Awareness among customers and quick action against culprits causing theft surely minimize the losses due to theft and uninterrupted power supply can be made possible for consumers.
Gyan Prakash Nirmal completed graduation in Electrical Engineering from MMMUT Gorakhpur. Presently, he is working as a Test Engineer in Energy Meter Testing Lab CPRI, Bhopal and having experience of four years in field of testing and certification of energy meters.
Deepa Warudkar completed graduation in Electrical Engineering from Nagpur University and M. Tech in HEE from MANIT, Bhopal. Presently, she is working as a Test co-ordinator in Energy Meter Testing Laboratory CPRI, Bhopal. She has more than 20 years of experience in all types of Energy Meter Certification Testing and Development Testing.
