1. Preliminary understanding of complete electrical equipment

Guizhou electrical equipment price discussion as a complete electrical equipment quotation, first of all, we should know what is electrical complete equipment. Electrical complete equipment refers to the complete equipment composed of shell, bus, primary and secondary components, auxiliary materials, etc. it plays the role of receiving and distributing electric energy in the power grid, as well as controlling and protecting the power equipment. Electrical complete sets of equipment mainly include low voltage, medium and high voltage and box transformer.

2. Learn and master the basic knowledge of electrical equipment

The bidder of electrical complete equipment must be able to understand and understand the primary system diagram, secondary schematic diagram, layout plan and the relationship among the three. This requires the bidder to read more, learn more and ask more.

In a complete set of electrical equipment, the equipment composed of busbar, disconnector (high voltage), knife switch (low voltage), circuit breaker (air switch), voltage transformer, current transformer, AC contactor, protection relay (thermal relay), lightning arrester, etc. is called primary equipment. The circuit composed of them according to the principle relationship is called primary circuit or primary scheme diagram. In order to ensure the safe, reliable and stable operation of the primary system, monitor the operation status of the primary system at any time, and control many other electrical components and equipment necessary for the primary system at any time, such as: measuring instruments (ammeter, voltmeter, power factor meter, power meter, frequency meter, etc.), control signal elements (signal lamp, button, universal transfer switch, etc.), relay The circuit composed of electrical protection devices according to the principle relationship is called secondary circuit or secondary scheme diagram.

At the same time, the bidder of complete electrical equipment must be familiar with and master the common technical data. It includes: selection table of theoretical weight and current carrying capacity of busbar, comparison table of load and insulated bus cross section, clear distance between each phase conductor in cabinet with air as insulating medium and ground, specification and weight of hot rolled equal angle steel and common channel steel, power frequency withstand voltage level, etc.

3. Understand the price composition of complete electrical equipment

a. The price of primary and secondary components, usually strengthen the collection and collation of component price data, and timely grasp the change of component price;

b. Price of auxiliary materials, including: secondary wire, terminal, nose, clamp, winding tube, number tube, character code, tie tape, standard parts, etc;

c. The price of bus bar and the quantity of bus bar shall be estimated according to one-time scheme diagram;

d. Shell price shall be quoted by professional shell manufacturer according to one-time scheme;

e. Packaging and transportation costs;

f. Comprehensive expenses of enterprises, including management fees, labor wages, taxes and profits, etc;

g. Other expenses, such as paying certain fees to the bidding company in case of winning the bid.

4. Quotation process and precautions

a. Comprehensive digestion of drawings: according to the drawings provided by users, first check the list of drawings, and then assign and classify them. Understand the design intention of the project according to the design description and technical requirements of the drawings (for those with bidding documents, it is also necessary to combine the technical requirements of the bidding documents), consider the price of variable scheme, and pay attention to the plane layout (the plane layout reflects whether there is bus bridge between cabinets and the length of bus bridge).

b. Related precautions:

① In terms of high voltage cabinet, in order to meet the five prevention requirements, the incoming cabinet shall be equipped with live display and electromagnetic lock, and the outgoing cabinet shall be equipped with live display and grounding switch interlocking device.

② When the two-way power supply incoming line, the standby automatic switching device shall be considered, and the electrical and mechanical interlocking device (three in two) shall be considered between the two-way power supply incoming line and bus coupler.

③ Sulfur hexafluoride ring main unit and kyn28-12 central cabinet generally need to be equipped with temperature and humidity controller and heater.

④ When the distance between phases and ground can not meet the requirements of electrification, vulcanization treatment of bus bar or special-shaped busbar or heat shrinkable bushing of busbar shall be adopted, and the joint shall also be covered with insulating cover.

⑤ Understand the significance of low voltage moulded case circuit breaker accessories.

⑥ Understand the structure of low voltage draw out switch cabinet

⑦ Effective installation dimensions of electrical components in GGD housing

Calculation of Guizhou electrical equipment price for low voltage cabinet bus: the single assembly of upper incoming line of transformer and three-phase main busbar of contact cabinet is about 16m (when the cabinet width is 800mm). When the incoming line cabinet is equipped with metering, the installation position of knife switch and air switch will be moved down due to the space occupied by metering transformer and meter, so the length of busbar should be lengthened by about 0.6m per phase; when the bus length is greater than 6m, the connection between buses should be considered; when the bus is double or triple assembled, cushion block should be considered; when there are many incoming and outgoing cables, horizontal outgoing line should be considered.