Car Maintenance Shop Calculation

Contents

Scope and content of the course project

Course design consists of explanatory note, theoretical task, calculation part, graphic part

Theoretical part:

Job for Course Project

Brief description of the object

Schematic Design and Power Network Design

Design Part:

Calculation of electrical loads of power supply units and the entire object

Calculation and selection of distribution network

Calculation and selection of protection devices of distribution network

Calculation and selection of power supply network

Calculation and selection of power supply protection devices

Calculation and selection of lighting network

Calculation and selection of compensating devices

Calculation of number and power of transformers

Design Equipment Specification

Graphic part:

Power Electrical Plan

Electrical network diagram of the workshop

Substation Layout and Design

Introduction

The course project presents the car maintenance workshop. It is designed for servicing and repair of cars, as well as the production of products on lathes or other types of machines and the manufacture of various products from it. The length of the workshop is 54 meters, width - 39 meters. The total number of electric receivers in the workshop is 40 pcs. Metalworking machines and fans operate in long-term operation. Cranes operate in re-short-term mode. The mode is considered time-repeated if the cycle time does not exceed 10 minutes. Cranes have duration of IR actuation = 25%. IR is expressed in relative units or percentage. But when calculating electrical loads, IR is taken only in relative units. Complex transformer substations are used to power workshop electric receivers. KTP have 1 or 2 transformers.

Most often, in-house or attached (in-house is used in this workshop) are used because it is more economically profitable to keep the power supply closer to the center of the load.

Stand-alone substations are used in the following cases:

Consumers of other workshops are fed from KTP.

The room is explosive.

You cannot arrange according to the conditions of the technology.

In this case, a network with a blind-grounded neutral is used. In this mode, 110 KV and higher voltage networks and internal networks Un = 380/220 V operate.

The main reasons for grounding in such networks are.

Ensuring the safety of maintenance personnel, since high ground fault currents significantly increase the sensitivity of protective devices.

If the mains phase is damaged, the voltage at the 2 undamaged phases will not change.

In this case, a voltage of 380/220 V. This voltage is most widely used to power industrial and household consumers.

A large number of BP in the industry have medium and low power, so they work with Un = 380 V.

Power (Un = 380V) and lighting (Un = 220V) networks can be supplied from one transformer.

According to the reliability of power supply, according to the requirements of the PUE, electric receivers are divided into three categories:

Category 1 - includes EPs, the break in the power supply of which can entail for the life of people, significant damage to the national economy, etc. Category 1 EP shall provide power supply from 2 independent mutually redundant power supplies, their power supply interruption may be available only for the time of automatic switching on of the reserve.

The 2 categories include EP, which are recommended to provide electricity from 2 independently mutually redundant power sources. For this category, interruptions in the power supply for the time required to turn on the backup power are allowed by the actions of the duty personnel.

This power supply reliability workshop belongs to category 3 as it fits the definition of category 1 and 2. This workshop uses a combined power distribution scheme. It includes a radial and a trunk. The most part is used, because it includes the advantages of both schemes.

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