Welding shop power supply

Contents

Introduction

Source Data

Selection of voltage and neutral mode for shop switchgear

networks

Calculation of electrical loads of the workshop with regard to lighting

Power calculation of compensating devices (CP), selection of quantity and power of step-down transformers of shop TP, selection

rational variant of CP placement

Location Selection of Shop TP, Definition of Layout and Configuration of Shop Distribution Network

Calculation of loads of certain sites of shop network, choice of sections of sites, choice of the switching and protective equipment

Cell selection 6 - 10 kV, section calculation of high-voltage cable, calculation of protection setpoints on the 6 - 10 kV side

Calculation of short circuit currents in the shop network, check of electrical equipment for resistance to short circuit currents, check of protection sensitivity

Calculation of voltage losses, selection of PBV stripping of shop transformer

List of sources used

Introduction

The power supply system of the workshop, consisting of electrical networks with voltage up to and above 1kV, transformer and converter substations, serves to transfer electricity from the power source to the consumption place in the required quantity and of the appropriate quality.

The power supply system of the workshop should be flexible, allow constant development of technologies, increase in the capacity of the workshop and allow changing production conditions, as well as meet the requirements of reliability, economy and service safety. Therefore, consideration of:

- brief description of the workshop, its technological process;

- characteristics of the environment of production premises;

- brief characteristic of electric receivers and requirements for reliability of their power supply.

Knowledge of the process of the designed workshop makes it possible to correctly determine the basic requirements for the power supply system in terms of reliability of operation. Knowledge of the environment is necessary for correct selection of electrical equipment and execution of electrical networks.

Selection of voltage and neutral mode for shop distribution network.

In the designed workshop, the voltage of 380/220V is the main one, since all electrical installations are designed for this voltage. Therefore, the voltage value for the shop distribution network is U = 380/220B.

We choose a network with a blind neutral ground. Such neutral mode eliminates significant excess of rated mains voltage relative to ground. For this workshop, we select a four-wire TNC system with a grounded neutral, the housings are busy (connected by a conductor with a neutral source), in the fourth wire the functions of the working neutral and the grounded conductor are combined.

Advantages of the chosen system: TNC system is cheaper compared to TNS due to elimination of the 5th wire and switch, ease of protection, does not require constant operational supervision, savings due to opt-out.

Disadvantages: currents flow through the PEN conductor, uninterrupted power supply is low, high fire danger caused by a large current of a single-phase short circuit, the need to check the resistance of the phase-zero loop.