Metering cabinet, the cabinet with a special meter (device) installed, is called a metering cabinet. In China, the metering cabinet generally refers to the electric energy metering cabinet, according to the definition of terms in the specification "Electric Energy Metering Cabinet" (GB/T 16934-2013), the electric energy metering cabinet: a special cabinet type of electricity metering device (electric energy metering device). Electricity metering device: A general term for the combination of all electrical equipment, electrical parts and mechanical structures that measure electric energy.

First, the configuration of the metering cabinet

Users of power supply of 10kV and below should be equipped with a national unified standard electric energy metering cabinet (box). Users with 35 kV power supply should be equipped with a national unified standard electric energy metering cabinet (box).

Second, the measurement of security measures

The connecting parts of the measuring cabinet (box) and the secondary circuit must be able to reliably install seals, and the design of the sealing parts is scientific and reasonable, leaving no gaps; For the old metering device, the technical transformation should be gradually carried out on the premise of ensuring the measurement safety measures.

3. Selection and configuration of transformer

1. The metering cabinet (box) must be equipped with a special current transformer.

2. It is not advisable to use multi-tap variable ratio current transformer.

3. The relay protection and ammeter of the inlet cabinet should be equipped with a separate current transformer.

4. The determination of the rated primary current of the current transformer should ensure that the actual load current in normal operation reaches about 60% of the rated value, and at least not less than 30%.

5. The determination of the rated secondary load of the special transformer should ensure that the actual secondary load is within the range of 25%-100% rated secondary load.

Fourth, the measurement accuracy level configuration

1. High-voltage billing users with an average monthly electricity consumption of 5 million KwH and above, or high-voltage billing users with a transformer capacity of 10,000 KVA and above, must be equipped with 0.2 s current transformers; Class 0.2 voltage transformer; 0.2 S or 0.5 S class energy meter.

2. High-voltage billing users with an average monthly electricity consumption of 1 million kWh and above, or high-voltage billing users with a transformer capacity of 2000kVA and above, must be equipped with a 0.2 s current transformer, a 0.2 voltage transformer, and a 0.5 s or 0.5 level electric energy meter.

3. Billing users with an average monthly electricity consumption of 100,000 kWh and above, or billing users with a transformer capacity of 315 kVA and above, must be equipped with a 0.5 s current transformer, a 0.5 voltage transformer, and a 1.0 level electric energy meter.

4. Billing users, three-phase low-force users, and single-phase users with transformer capacity below 315 kVA should be equipped with 0.5 S level current transformer and 2.0 level electric energy meter.

Fifth, the measurement of the secondary circuit

1. The secondary circuit of the voltage transformer in the charging energy metering device of 35 kV and below shall not be equipped with the auxiliary contact and fuse of the isolation switch.

2. The electric energy metering device must be equipped with a joint junction box, and the secondary circuit of the voltage transformer should be directly connected to the electric energy meter through the joint junction box, and shall not be connected through the terminal bar.

3. The connecting wire from the secondary outlet terminal of the transformer to the inlet terminal of the joint junction box shall be made of copper single-core insulated wire; A, B, C phase wires and neutral wires are distinguished by yellow, green, red and two-color wires respectively, and must be wired in phase order.

4. The two ends of the connecting wire from the secondary outlet terminal of the transformer to the joint junction box should be numbered, and the handwriting should be clear and durable.

5. For the current secondary circuit, the cross-sectional area of the connecting wire should be calculated and determined according to the rated secondary load of the current transformer, and should not be less than 4mm2. For the voltage secondary circuit, the cross-sectional area of the connecting wire shall be determined according to the calculation of the allowable voltage drop, and shall not be less than 2.5mm2.

6. The length of the secondary wire from the transformer to the joint junction box should be left in the form of coiling (about 30cm) in the form of coiling, so that the wiring can be adjusted in the future.

7. The high-voltage metering cabinet should be equipped with a split-phase voltmeter, and the connecting wire of the voltmeter should be a soft wire to distinguish it from the metering secondary circuit wire.

Sixth, the design and installation of the electric energy meter box

1. There should be a space of 8-10cm between the bottom of the electric energy meter box and the lower edge of the joint junction box to the lower edge of the joint junction box.

2. The size of the electric energy meter box should ensure the space of two meter points, the electric energy meter is installed on one side, and the meter position on the other side is reserved for the remote meter reading terminal equipment, and the depth of the electric energy meter cabinet is not less than 16 cm.

3. The size of the window of the electric energy meter box should be able to meet the needs of copying the electric energy meter electricity and parameters.

4. The backrest bottom plate of the electric energy meter should be convenient for the front installation and replacement of the electric energy meter, and meet the insulation and flame retardant requirements.

5. Other components unrelated to the electric energy meter and remote meter reading terminal equipment shall not be combined with the electric energy meter.

6. On both sides of the front of the bottom plate of the measuring cabinet, a cable hole with a diameter of 5 cm should be left for each negative pipe device.

7. The instrument box of the inlet cabinet should be preset with a joint junction box, and the current line bow f is from the secondary side of the current transformer of the inlet cabinet; On the panel adjacent to the meter box and the metering cabinet energy meter box, a cable hole with a diameter of 2.5 cm is reserved to make the two boxes penetrate.