At almost constant power factor and voltage by monitoring the output current from KWH meters and the supply current to factory with clip on meter, would give the energy theft……
Yes. The answer depends on various approches available for the solutions. I will like to delineate the solutions to the problem as follows.
1. To temper with the meter requires the intruder to make some connections that are different from authorised working mode. So, there will be some changes to the wire connections. Since the meter can be construed as a state machine in system emgineering lingo, reprogramming can be done to the system firmware right from onset. This requires no intrusive encounter with the meter.
2. If option number seems too daunting, there is opinion that the wire terminal is installed with one way clip. Any temper will render the clip useless. Also, the clip can be tagged officially by distribition company.
3. There are still more game theoretic means to check for unofficial engagement with electrical meters.