CNA multifunctional electricity meter refers to an electricity meter that, in addition to measuring active (reactive) energy, also has functions such as time sharing and measuring demand, and can display, store, and output data. It has a number of working conditions, mechanical requirements, electrical requirements and performance requirements, including Electromagnetic compatibility, requirements for key components and time-sharing functions.
A multifunctional electricity meter refers to an electricity meter with two or more functions, which can perform metering, time sharing, measuring demand, and other operations, and can display, store, and output data.
1、 Product features:
Multifunctional electricity meters have the following characteristics:
The standard reference voltage is 220V.
The standard reference current can be selected as 5A, 10A, 15A, or 20A.
The maximum current is 4 times or more of the rated current, and the instrument should not be damaged when operating at 1.2Imax for 1 hour.
The standard reference frequency is 50Hz.
2、 Mechanical requirements:
The watch case should have double-sided clamp seals, and only after breaking the clamp seal can the internal parts of the watch be touched.
The enclosure shall be sealed, dust-proof and have a certain strength. It shall be made of flame retardant materials, resistant to deformation, aging and high transparency.
The bottom shell should be connected to the bottom plate of the end button box and have non combustible properties. Temperature requirements for terminal blocks and covers: 960 ℃± 15 ℃; The temperature requirement for the watch case: 650 ℃± 10 ℃; Action time: 30s ± 1s.
The LCD display should have a 6-digit display, with 5 digits being integers and 1 digit being decimals. The minimum memory time for non volatile memory should be 4 months.
The meter should have a test output device that can be contacted from the front and monitored using appropriate testing equipment.
The wiring diagram should indicate the wiring method and be the same as the 86 series electricity meter.
The accessories in the table should have the ability to prevent rust and oxidation.
The nameplate should be clearly visible, resistant to ultraviolet radiation, non fading, and have a barcode that complies with the coding rules of the barcode.
3、 Electrical requirements:
1. Power consumption: Under reference voltage, temperature, and frequency, the active power and apparent power of the voltage line of the electric energy meter should be less than 1W and 6VA; The apparent power of the current circuit should be less than 1VA.
2. Voltage and voltage impact: The operating range is 0.9Un to 1.1Un, and the maximum operating range is 0.7Un to 1.3Un. After applying 380V voltage to the voltage line for 1 hour, the meter should not be damaged and can operate normally.
3. Power interruption impact: After the tests specified in the regulations, the power interruption should not have a substantial impact on the electricity meter.
4、 Electromagnetic compatibility:
Comply with the requirements of GB/T17215-1998 and DL/T614-1997.
The design of the meter should ensure that it will not be damaged or substantially affected by electromagnetic disturbances such as conduction and radiation, as well as electrostatic discharge.
5、 Key component requirements:
1. Chip: The variation rate should be within ± 0.1%, and the linearity should be within ± 0.2%, using the American ADE7755 chip.
2. Electrolytic capacitor: temperature resistance 105 ℃, leakage current shall be less than 3 within 3000 hours μ A. Withstand voltage shall be greater than or equal to 16V, and Japanese Ruby Electrolytic capacitor shall be used.
3. Current limiting capacitor: Made of polystyrene metal film, with a capacity of 0.33 or more μ F. Use Philips current limiting capacitors.
4. Varistor: the nominal voltage is 20K, the voltage ratio should be less than or equal to 1.15, and the leakage current should be less than 30 μ A.
5. Sampling resistance: Made of manganese copper alloy, subjected to passivation treatment and high-temperature aging.
6. Crystal oscillator: produced by imported parts or joint ventures.
7. Chip resistors and chip capacitors: produced by imported components or joint ventures.
8. Voltage regulator diode: Imported components are used.
9. LED: Made of low-power imported components.
6、 Performance requirements:
1. The basic error should meet the requirement of level 2.0.
2. Acceptance error limit: meet the technical specification requirements under the specified reference conditions. Conduct acceptance according to 50% of the error limit specified in the verification regulations.
3. Error limit during operation: meet the requirements of technical regulations under specified reference conditions.
4. Limit of error change caused by other influencing factors: The additional percentage error change caused by changes in the influencing factors relative to the reference conditions given in the regulations should not exceed the limit specified in the regulations.
5. The impact of environmental temperature: The average temperature coefficient should not exceed the limit specified in the regulations.
6. Time sharing function: supports three rates and can display the hourly and total electricity consumption for a specified time period. The daily timing error should be less than 0.5 seconds per day.
7. Meter reading: supports infrared programming meter reading, and the communication protocol is executed according to DL/T 645-1997.
8. Output port: Equipped with standard pulse output and LED output, corresponding to the electrical energy value.
9. Electric meter error guarantee period: Under normal working conditions, the average service life of the electric meter is at least 10 years.
10. Battery: Using cylindrical batteries with a minimum lifespan of 10 years.
The above are the requirements and performance indicators for multifunctional electricity meters. It can not only measure active (reactive) electrical energy, but also has various functions such as time sharing and measuring demand, and can display, store, and output data. The shell of the electric meter should meet the requirements of dust prevention, strength, and sealing, while also meeting the standards of mechanical, electrical, and environmental conditions. Key components such as chips, Electrolytic capacitor and current limiting capacitors also have corresponding requirements. In terms of performance, the meter should meet various indicators such as basic error, environmental temperature impact, and time sharing function, and support meter reading and have output interfaces.
