Exchange rate project assembly shop - power supply

Introduction

As investment in the national economy grows, the volume of ERM increases continuously. The systematic growth of volumes, the need to reduce the time for commissioning of construction facilities, requires electricians to further improve the organization of ERM production. In recent years, labor productivity has been increasing due to industrialization and mechanization of work along with the tasks of increasing productivity by installation methods and turning work in the installation zone into assembly, laying and installation of pre-fixed electrical units. The decisive condition for the further improvement of the ERM organization, the hanging of the level of production preparation, the development of the productivity of large-unit equipment and prefabricated complete devices are also important for electrical installation, as for housing construction, as industrial structures.

Brief description of the installation object

In the course work there is an assembly shop. It represents a single-story building. Length 54m, width 24 and height 9 meters. The total number of electric receivers in workshop 61. All electric receivers of this workshop operate in long-term mode.

For power supply of shop electric receivers, an attached FTP is used, which has one transformer (according to PUE 3 reliability category). Since the power consumption of the workshop is 300 kVA, it is powered by 400 kVA KTP 10/0.4 kV.

In this case, a network with a grounded neutral is used. A large number of BP has medium and low power, therefore they work with Un = 380 V. In this mode, networks with Un = 110 kV and above and inside shop networks operate: power network Un = 380 V and lighting network Un = 220 V.

As for the distribution of energy in the caterpillar workshop, this happens as follows: from the FTC, voltage is supplied to the electrical panel workshop, then from the panel to the distribution cabinets, and from them to the electric receivers. From the FTP to the panel shop, electrical power is supplied by a cable laid in a trench, from the panel to distribution cabinets - by a cable laid on the CCS or on trays, from the SR to electrical receivers - by a cable laid in pipes in the floor of the shop.

This workshop uses a combined power distribution scheme. It includes a radial and a trunk.

The power network is made of five-core cables: three phases (l1, l2, l3), zero working, zero protective; and the lighting network with three-wire wires: (l - phase, N - working zero, NE - protective).

Installation of grounding loop

Installation of the execution grounding loop in the following sequence:

1. Read Project

2. Digging trenches

3. Deepening of electrodes

4. Laying of horizontal earthing

5. Welding of connections between horizontal and vertical earths

6. Connection to the network of internal grounding circuits.

7. Inspection of welding places

8. Filling of welding places

9. Preparation of the act on hidden works

10. Backfilling of the trench

11. Ground loop test with report.

Grounding is performed in order to ensure the safety of people in case of violation of insulation of current-carrying parts and to create normal operation modes of electrical installations, as well as to protect electrical equipment from overvoltage and lightning protection of buildings and structures.

Outer circuit consists of vertical and horizontal grounding and branch conductors connecting grounding parts of electrical installation with grounding. First of all, natural grounding conductors are used, water pipes and other metal structures laid underground, with the exception of pipelines of combustible liquids and gases. If it is impossible to use natural grounding conductors or their insufficient conductivity, artificial grounding conductors are mounted. Artificial earth conductors are also required in installations above 1000 V with high ground fault currents.

Artificial earthing conductors use both vertical and horizontal. Vertical grounding conductors (electrodes) are made in the form of rods made of steel 12-16 mm, 5 m long, buried in the ground by special devices. In combination with vertical, horizontal grounding conductors are used - steel strips with a thickness of at least 4 mm or round steel with a diameter of at least 6 mm. Sometimes the grounding circuit is performed only by horizontal grounding conductors. The outer circuit of vertical and horizontal grounding is mounted in a trench with a depth of 0.8-1 m. Vertical grounding electrodes are immersed in the ground in previously designated places so that their vertical ends protrude 200 mm above the bottom of the trench. Horizontal grounding conductors are laid and connected to vertical ones by welding.

A network of grounding lines and grounding conductors is installed inside the buildings with the help of which electrical equipment is connected to the grounding conductors. In networks with a voltage of up to 1000 V, zero wire of the network, metal structures of buildings, etc. are used as grounding conductors.

Flat steel conductors are shot with dowels to concrete or brick bases, welded to embedded parts at a height of 0.4-0.6 m from the floor. The attachment pitch of the highways is 600-1000 mm. Grounding conductors shall be protected against mechanical damage, their passes through walls and ceilings shall be made in pipes, connection of grounding conductors shall be performed by overlapping welding.

Installation of Power Networks

Installation of power networks and equipment is carried out in two stages:

First stage of electrical installation works:

1. Read Project

2. Procurement of wires and cables in MZU

3. Procurement of structures in MZU

4. Hardware Validation and Debugging

5. Acceptance of installation room

6. Marking of attachment points

7. Installation of embedded parts

8. Piping Workpiece

9. Packing of wire blanks and structures in containers.

Second stage:

1. Delivery of materials to the installation area

2. Installation of mounting structures equipped with

3. Pipe Preparation for Wire Tightening

4. Routing of Wires and Cables

5. Installation of boxes equipment

6. Installation of control boards:

a) Drill holes

b) Lay spacer dowels

c) Attach structures

d) Install panels

e) Connect to supply line

f) Connect outgoing lines

g) Marking

h) Perform visual inspection of works performed

7. Measure insulation resistance

8. Debug and test the equipment

9. Draw up protocols

During the construction of the building in concrete floor preparation, pipes are laid for wiring protruding 200 mm from the mark of the clean floor. At the ends of the pipes there is a thread protected from damage by special caps. After complete completion of finishing works, pipe section of required length or metal tubes is connected to pipe end protruding from the floor by means of coupling. A wire hole is punched in the body of the apparatus, and branch pipes are mounted to enter them. The coupling is screwed along the long thread of the branch pipe and simultaneously screwed onto the thread of the pipe, fixed with a lock nut. Wires or cables that connect to instruments are tightened into pipes.

Electric machine control devices, assembled units on steel structures or insulated plates, are installed in steel cabinets (and only in special electric machine rooms open). Installation of units in cabinets is carried out in workshops of MZU. They can come from manufacturers in a ready-made form. Installation of such units shall be limited to installation of cabinets on frames embedded in concrete floor preparation together with pipes for wiring to the cabinet of wires and cables.

Installation of distribution boards, as well as control boards, consists of installation of panels on a prepared and carefully adjusted base, consisting of channels w8 and w10 laid on concrete structures in strict accordance with the drawing, as well as connected wires and cables to instruments and devices installed on them.

According to the installation method, the shields are divided into: separate and leaning, one-sided and two-sided services. The design of free standing boards allows them to be installed in any part of the room without additional support to the wall. Panels of control boards pass the strengthening assembly in workshops. Dismantled devices and devices requiring special care during transportation are installed after the installation of the control boards is completed.

Adjustment of Electrical Equipment

Adjustment of devices with voltage up to 1000 V.

Adjustment of contactors, magnetic starters, magnetic and thermal relays. General instructions for checking equipment.

Equipment inspection, testing and adjustment shall include:

1. External inspection

a) Check of EMF completion;

b) Compliance of installed devices and devices with load current and its operating conditions;

c) Conformity of voltage of coils and windings to voltage of mains;

d) Correspondence of thermal elements of the relay to the current of the protected engine and their serviceability;

e) No additional heating sources near the thermal relay;

f) Absence of mechanical damages.

g) Correct installation of devices and reliability of their attachment

h) Condition of all contacts of the set;

i) Absence of dust, dirt, rust;

k) Absence of gaskets;

l) Absence of precos, freewheeling;

m) Availability and serviceability of return springs;

n) Reverse starters shall check operation of mechanical interlock;

2. Insulation resistance check is measured by megohmmeter, when connecting wires coming from its clamps, between current-carrying parts and current-carrying part and housing.

3. Measurement of coil resistance.

The switching capacity of the set is affected by the nature of the load. Contactor system parameters. Solution of contacts distance between contactor surfaces of movable and fixed contacts in open position.

Current passing through the contacts is influenced by the transition resistance at the point of contacts due to the presence of oxide films on the contacts. During adjustment of the devices, the density of fixation of fixed contacts and the density of abutment in the on-line state are checked.

At definite voltage force of final contact, supply voltage is previously switched off and dynamometer is connected to movable contact. Paper is inserted between the movable and fixed contact, and the starter is switched on. Then suspension contact is pulled by dynamometer to free paper withdrawal.

Everything must comply with the passport data. With a certain initial incandescent force of the paper being laid under the spring and contact, the contactor is not turned on. With a dynamometer, the spring is pulled down until the paper is freely removed.

Recommendations on the environment.

As provided for by all "environmental protection" requirements, each enterprise has a special passport, which lists all emission media (if any) of reduction in the environment or waste received during the enterprise's activity in increase.

As for this workshop, it is more natural than waste-free production. All waste of this workshop is disposed of in a designated place.

There are also emissions of carbon dioxide into the atmosphere, in permissible amount.

All emissions and wastes meet the requirements, and are entered in the pass port of this workshop for the production of phosphors.

Recommendations on the environment:

- Install more modern filters, switch to newer equipment, revise production technologies.

With the achievement of at least those goals, the environment was improving.