Bagaimana untuk memilih satu-meter pintar fasa?
Penggunaan meter pintar-satu fasa digunakan terutamanya dalam meter elektrik isi rumah. Biasanya meter rumah dipasang oleh jabatan kuasa atau pemaju, tetapi terdapat tempat di mana satu-meter fasa mesti dipasang untuk mengukur meter kediaman atau sewa. Jadi berikut ialah cara memilih satu-meter pintar fasa supaya ia boleh digunakan pada masa hadapan.
1. Pengesahan julat
Mengapakah julat meter pintar-fasa tunggal mesti disahkan terlebih dahulu? Untuk kegunaan selamat masa hadapan, ia mesti dipastikan bahawa arus yang diukur meter tidak melebihi nilai yang diukur. Konfigurasi meter pintar-fasa tunggal mestilah berdasarkan kuasa hutang. Arus peralatan-satu fasa ialah 4.5A setiap KW, jadi julat meter hendaklah dikonfigurasikan menjadi 1.2-1.5 kali ganda arus. Jika jumlah kuasa perkakas rumah ialah 4KW dan arus ialah 18A, meter tenaga elektrik 5(20)Satu fasa boleh digunakan.
2. Pengesahan kapasiti
The typical voltage specification of a single-phase smart meter is 220V, and the current specification is 1.5(6)A 5(20)A 5(60)A 15(60)A 20(80)A, etc. The choice of specification at this stage is mainly based on the user's load. Usually, the upper limit of the load current cannot exceed the rated current of the electric energy meter, and the lower limit is not less than the load current specified within the allowable error range of the electric energy meter. For example, the total power consumption of the user is about 10KW, the voltage is 220V, and the current is 10000÷220≈46A. That is to say, the power is divided by 220, which means that a certain margin is fully considered, and the current value is about 46A. You can choose the current specification of 5(60) 15(60)A. You can also choose a smaller current size and connect a current transformer.
3. Selection of current transformers Current transformers are specially designed for high current users. It is capable of converting large currents with larger values to secondary currents with smaller values for safeguard and measurement purposes. For example, a 100/5 current transformer can convert 100A to 5A of current. The selection of current transformer specifications is mainly for low-voltage users. Low-voltage users may not be able to estimate power consumption due to random load variations. Therefore, the transformer specifications are not fixed. It is usually calculated based on known power. For example, for a user with an electric power of 100KW, the voltage is 220V, the current is equal to 100000÷220≈455A, and a certain margin needs to be considered. A 500A current transformer must be selected. The secondary output current of the transformer is usually 5A, so we choose a 500 to 5 transformer. The accuracy of the current transformer must be at least the same as the meter.
