Intelligent anti-theft energy meters are generally divided into the following two types according to their functional principles: one is that when users use several methods to steal electricity after passing the energy meter, the energy meter can still measure or measure faster. At present, Most anti-theft energy meters on the market are of this type. The other is that when a user passes through the energy meter and steals electricity, the energy meter immediately cuts off power and automatically resumes power supply immediately after the electricity stealing stops.
1. Change the general electric energy meter counter into a bidirectional counter with a reversing wheel mechanism. This counter is a patented product. When the electricity user changes the polarity of the current and voltage coils, uses stolen electrical appliances (the principle is to change the phase of current and voltage), or uses other methods to reverse the aluminum plate of the energy meter, the counter maintains the energy meter through the reversing mechanism. If the count is positive, the user cannot count down the counter by using the above method. As a result, the anti-theft electric energy meter has anti-reversal and anti-reversal functions.
1. Once the voltage coil hook in the junction box of an ordinary electric energy meter is removed, the electric energy meter will not rotate due to the voltage coil losing power, but the user can continue to use electricity. The anti-theft electric energy meter is A voltage hook was added to the meter cover, and the hook in the junction box was removed. There is still a hook in the meter that cannot be removed, making it impossible for users to use this method to steal electricity. During the business census, the power supply department discovered that many of the electricity thieves had removed the voltage hooks.
1. The current coil assembly adds a reverse-wound secondary current coil from the original single-winding main current coil. The forward and reverse-wound main and auxiliary current coils are connected in series and installed in the meter. The main coil of the anti-theft meter has more windings than the main coil of the ordinary meter, which just increases the number of turns of the rewinding secondary current coil. In this way, after the main and secondary current coils are connected in series, the rewinding part of the secondary coil offsets the number of turns in the main coil. The forward winding part of the winding, therefore, is also equal to the number of original winding turns in the general table. Assuming a DD862-5 (10) A meter, the current coil of the general meter is 8 turns, and the secondary current coil of the anti-theft energy meter is 4 turns (rewinding part), then the main current coil should be 8+4=12 turns. After the main and auxiliary current coils are connected in series, the 4 forward turns are offset by the 4 reverse turns. In fact, there are still only 8 forward turns, which is the same as the number of turns of the general meter current coil. 2 The second functional principle of the anti-theft electric energy meter.
This kind of anti-theft energy meter has a controller inside the meter. The controller is composed of transformer, relay and electronic circuit. The phase line and neutral line of the main circuit pass through the zero-sequence current transformer coil. During normal working hours, the currents on the two lines are equal in magnitude and opposite in direction. The signals induced in the transformer cancel each other out, and the output signal is 0. When the user When various means are used to steal electricity, the currents in the incoming and outgoing lines are different, and the currents on the two lines are not equal. When it exceeds a certain value, the relay will trip and cut off the power. This function is also suitable for leakage protection, so regardless of leakage or electricity theft, The energy meter shuts down immediately. After eliminating the above power stealing methods and leakage, the power supply will be automatically restored immediately.