Master The Common Sense Of The Electric Meter You Don't Have To Worry About How To Select The Electric Meter
Now electricity meters can be seen everywhere in our lives, and electricity meters will be installed wherever there is electricity. Now there are more types of electric meters, and now the functions of electric meters are also more, and it is no longer as simple as measuring. So how to choose the meter, you need to know this common sense.
1. Selection of metering accuracy
Our common precisions are 0.2S, 0.5, 0.5S, 1.0, 2.0. The smaller the value, the higher the accuracy. The single-phase meter can only achieve the highest level of 1 accuracy, and the three-phase meter can achieve the highest level of 0.1s, but generally, 0.5s and 0.2s are the main ones. The allowable error of a grade 1.0 meter is within ±1%. For every 100 kWh of electricity used, at most 1 kWh is allowed to be metered more or less. In reality, it is possible that some users have over-metered, and some have under-metered. But in fact, in order to pass the inspection, the meter factory has stricter control of the error, all within 0.6%, that is, only 1000 kWh of electricity will produce a difference of up to 6 kWh of electricity.
2. How to choose three-phase three-wire and three-phase four-wire
The difference between three-phase four-wire and three-phase three-wire is mainly the difference in wiring method, which is determined by the user's incoming line and the nature of electricity consumption. If the user is a pure three-phase electrical appliance, such as a three-phase transformer, a three-phase motor, etc., a three-phase three-wire meter can be used. The three-phase three-wire system can only provide 380V power supply. There are only three wires and no zero wire. When the load is unbalanced, the zero-phase feedback current cannot be passed, and it is easy to burn the electrical appliances. If the user has a single-phase load and a three-phase load (both 220v and 380v), a three-phase four-wire meter should be used.
3. Active power and reactive power
What is active electricity is actually very simple? Our general household meters are single-phase electricity meters and single-phase electricity meters measure active electricity. Generally, smart three-phase electricity meters can measure reactive electricity. So, what is the benefit of measuring reactive power? You can judge the ratio of power to active power by measuring reactive power and detecting the conversion rate of active power. Some devices must first establish a conversion environment when converting energy. For example, motors and transformers must first establish a magnetic field to perform energy conversion. The amount of electricity required to create a magnetic field is reactive energy. Generally, three-phase electricity meters are only used by large electricity consumption units.
Single-phase meters are all active meters, and the model of simple three-phase active meters is generally DTS. Active simple three-phase four-wire meter, this type of three-phase four-wire meter can only measure active meters. There is also DTX, which is a simple three-phase four-wire meter for reactive power, which is specially designed to measure reactive power. There are also three-phase smart meters and multi-function meters that can measure both active and reactive energy. The models are generally DTSD/DSSD/DTZ/DSZ, etc.
4. Select the meter according to the load
Single-phase electricity meters are generally straight-through electricity meters. Generally, electricity meters have current specifications. Now the unified specification of single-phase electricity meters is 5 (60) A, and a small amount of 20 (80) A. This type of electricity meter is enough. The 60A meter can support 13200W electrical appliances, which is enough for the daily electricity consumption of the family.
The commonly used specifications of three-phase electricity meters are 1.5(6)A, 5(60)A, 20(80)A, and 10(100) A. When selecting an electric meter, on the one hand, it should be noted that it cannot be lower than the basic current; on the other hand, it cannot be higher than the maximum rated current. Generally, there are more three-phase meters with 1.5(6) A. This type of meter needs to be added with a transformer. Generally, if the current that needs to be measured is greater than 100A, a 1.5(6)A meter is required.
