Zw8-12p Prepaid Metering Device

I. Overview

This type of pre-paid combined transformer is epoxy resin vacuum poured voltage and current transformer for measurement, ZW8 vacuum circuit breaker with spring mechanism, protective current transformer and zero sequence current transformer, external voltage transformer as switching power supply, and electric energy metering control box with intelligent controller. Type prepaid combined transformer (commonly known as watchdog type prepaid high-voltage metering box in the industry). The outdoor isolation knife gate can be selected to make the line have obvious breaking point under power failure. The circuit breaker has the functions of electric and manual energy storage, so that the line can be switched on and off in case of power failure. It is suitable for the prepaid metering and distribution of load current, overload current and short circuit current in branch and special transformer of power system with rated frequency of 50Hz and rated voltage of 6-10kV. It can provide users with 0.2S level products with various changes and double changes, measuring the main technical parameters: rated frequency 50Hz; rated primary current: 5-600A; rated secondary current: 5A or 1A; rated secondary voltage: 100V; circuit breaker switching power supply voltage: 220V. Because of the particularity of vacuum circuit breaker, it is especially suitable for frequent operation and oil-free transformation. The prepaid high-voltage metering device realizes the basic functions of prepaid electricity charges, warning before arrears, switching off after arrears and delaying alarm by prepaid control terminal. On the basis of the basic functions, it extends the intelligent judgment knowledge of overload and overcurrent protection, grounding protection, reclosing, remote control, telemetry, remote communication and so on. No function.

When a fault occurs in the user's interior of T-connection of 10 kV overhead distribution line, if the fault occurs in its entry section, or if the fault occurs in the inside of the user's entry switch, but the protection action time limit of the fault does not match the protection of the substation's outlet switch properly, the protection of the substation's outlet switch will turn off. If the nature of the fault is permanent and the substation overlap is unsuccessful, an accident within a medium-voltage user will cause power failure of the entire distribution line. This kind of common spread accident in the distribution network will have a bad impact on the society. This type of outdoor user demarcated vacuum circuit breaker is the ideal equipment to solve the aforementioned sweeping accident. The zero sequence current transformer is built in the outgoing side of the equipment, which is used in conjunction with the demarcation controller. Installed at T junction or user end of 10 kV overhead distribution line, the single-phase grounding fault can be automatically removed and the inter-phase short circuit fault can be automatically isolated. Ensure the safety of power consumption for non-fault users. Suitable for substation, industrial and mining enterprises, rural power grid distribution system for protection and control and frequent operation places.

II. Citation criteria

GB/T 1022-1999 Common Technical Requirements for Standards of High Voltage Switchgear and Control Equipment
GB311.2-2002 "Guidelines for Insulation Coordination of High Voltage Transmission and Substation Equipment"
GB/T 4109-2008 "Insulation Casing with AC Voltage Above 1000V"
GB2706 "Test Method for Dynamic and Thermal Stability of AC High Voltage Electrical Apparatus"
GB3309-1989 Mechanical Test of High Voltage Switchgear at Room Temperature
GB1208-2006 Current Transformer
GB/T17626-4-1998 EMC Test and Measurement Technology, Electrical Fast Transient Pulse Group Immunity Test

III. Environmental Conditions

A. Elevation not exceeding 2000 meters; Pollution grade: Grade IV.
B. ambient air temperature: - 40 C ~ + 40 C; diurnal temperature difference: diurnal variation 25 C.
C. Wind speed is not more than 35 m/s and earthquake intensity is not more than 8.
D. Places free from flammability, explosion and chemical corrosion.

IV. Analysis of Structural Advantage

The overall structure of this type of outdoor user demarcated vacuum circuit breaker is three-phase common box type. The box body is dry air, and the spring operating mechanism is arranged on the side of the box body.

1. The circuit breaker body is mainly composed of conductive circuit, transmission system, insulation system and so on.

2. Conductive circuit consists of conductive rod, conductive bracket and vacuum interrupter. Vacuum interrupter adopts ceramic shell, cup-shaped longitudinal magnetic field contact structure and copper-chromium contact material. It has good ability of breaking and closing short circuit current and long electric life.

3. The transmission system consists of three-phase rotating shaft, insulating tie rod, turning wall, contact spring and brake spring.

4. Insulation system in the interior of the box is separated by three-phase insulation cover. Conductive pole is enclosed with organic insulation material. It is a typical air-solid insulation structure, which overcomes a series of problems caused by oil filling and gas filling. The outer part of the conductive pole box (external insulation) is covered with silicone rubber umbrella skirt besides organic insulation. Silicone rubber insulation material has the advantages of anti-condensation and anti-pollution, so the insulation performance of circuit breaker is reliable, and it can operate safely in harsh weather conditions and polluted environment.

5. Circuit breakers are equipped with current transformers, which can be installed with specifications of 50/5, 100/5, 200/5 and 400/5 according to user's needs.

6. Manual operating mechanism is composed of closing spring, energy storage system, over-current tripper, opening and closing system, which can be divided into manual and electric operation.
Manual operation mechanism has the functions of manual energy storage, manual switching and over-current protection. If users need it, surge current delay protector can be installed to prevent misoperation of switching.
Electric operating mechanism should be powered by independent power supply. Besides electric energy storage, electric switching and over-current protection, it also has the functions of manual energy storage, manual switching and over-current protection. Surge current delay protector can also be installed if users need it.

7. The structure of combined circuit breaker is mainly composed of contactor, bracket, insulating support and rotating shaft. A mechanical interlocking device is installed between the circuit breaker and the disconnector, which has the function of preventing misoperation. The mechanical interlocking device has the following functions:

A. When the circuit breaker is in the closing position, the disconnector can not be switched off; only after the circuit breaker is switched off, the disconnector can be switched off.

B. When the circuit breaker is in the opening position, the disconnector can not close; only when the circuit breaker is in the opening position, the disconnector can close.