110/10 kV substation design

Contents

INTRODUCTION

1. Selection of type, number and power of power transformers

1.1 Selection of type of power transformers

1.2 Selection of number and power of power transformers

2. Select the electrical diagram of the substation. Selection of main substation design solutions

2.1. Select Electrical Connection Diagram

2.2. Selection of main design solutions for substation

3. Calculation of short-circuit currents

4. Selection of electrical devices

4.1.Selection of high-voltage switches

4.2. Selection of current transformers

4.3. Selection of disconnectors

4.4. Check of equipment on the 10 kV side

5. Selection of operating current, measurement system, auxiliary transformers

5.1. Selection of operating current

5.2. Selection of substation auxiliary transformers

6. Calculation of substation lightning protection

6.1 Protection area of the double rod lightning diverter

CONCLUSION

LIST OF SOURCES USED

Introduction

What is the main goal of the electricity industry today? Electricity is a collection of systems and infrastructures that are primarily designed to provide quality service and supply any consumer with electricity. The main task is to properly ensure the supply of electricity to the consumer, complying with strict requirements, such as: continuity, reliability and quality of service. If at least one of the requirements is violated, such consequences as: accidents, damage to electrical equipment, underdelivery of the enterprise's products, and as a result - losses are inevitable. How to prevent such situations? When designing, it is necessary to use ready-made, standard technical solutions that are optimal and reliable, and also use high-tech solutions to ensure the quality of the power supply system. One of the most important stages is the design of substations, which is a set of high-tech solutions, the choice of the location of the substation and the composition of the equipment necessary for the full functioning of the power supply system.

The purpose of the course design is to calculate and select the necessary technological solutions when designing the electrical part of the lowering substation as 10/10 kV. The objective of the project is to:

- select the type, number and power of power transformers;

- select electrical connection diagram;

- calculate short circuit currents;

- select high-voltage equipment for 110 and 10 kV side;

- drawing of the substation schematic diagram;

- draw the substation plan.

Selection of type, number and power of power transformers

Selection of type of power transformers

In order to select the type of power transformer required to be installed in the substation, the following requirements shall be followed:

a) three-phase transformers should be chosen, in particular cases - single-phase, it is also possible to use similar three-phase transformers - autotransformers

b) in case the substation is designed for three voltage levels, three-winding transformers are used

c) In order to power consumers separately, it is recommended to use transformers with split load, in the presence of a sharp variable load.

d) Need for a voltage control device on transformers under load

In our case, the choice fell on a transformer of the TRDN type, which has a RPN device, oil cooling with a blow, is a three-phase transformer with a split winding.

Selection of main design solutions for substation

Now it is necessary to substantiate all the design solutions that we have chosen that will be applied during the design, according to the regulatory requirements used in the development of electrical substations.

Since the designed substation in our case is designed for a voltage of 110 kV on the high side (HV) and 10 kV for the low side (LV), for the HV side we will use an open switchgear (ODS), according to the recommendations, for a voltage of 35 kV and higher, that is, when all or the main equipment of the switchgear (RP s) is located outdoors. And for the LV 10 kV side we use a complete switchgear (KRU).

As current-carrying parts, a combined sheath is used: rigid and flexible in different areas of the switchgear, but in our case a flexible sheath will be used.

To date, gas-insulated or vacuum switches are also provided, which have replaced obsolete oil and air switches.

When the use of built-in current transformers does not provide the required relay protection forces, power metering and power supply systems of measuring instruments, it is recommended to use separate current measuring transformers [7].

To prevent oil spreading and fire spread in case of damage to oil-filled power transformers, oil receptacles should be made, where a layer of gravel with a thickness of at least 25 cm is laid, oil drains and oil collectors, where oil flows in emergency cases, everything is done in accordance with the requirements of PUE.

The substation structure shall be protected by lightning rods [3, 5, 7].

For 10 kV voltage, packaged switchgears are usually used - these are switchgears consisting of closed cabinets (metal cells) or units with built-in devices, measurement, protection and automation devices and connecting elements supplied in assembled or fully prepared for assembly.

Closed type RVs may be used: (1) in areas where climatic conditions, atmospheric pollution conditions or snow drifts do not allow the use of RVM; 2) with the number of cabinets more than 25; 3) if there is justification [7].

Cabinets are provided with vacuum and gas-insulated switches, with a pre-selected type of electrical and switching equipment by the manufacturer, and supplied in various versions.

Selection of operating current, measurement system, auxiliary transformers

5.1 Selection of operating current

For normal operation of instruments and devices of control and alarm, as well as for power supply of operational circuits of relay protection and automation, an operational current source is required. Direct, rectified and alternating operating current is used.

In accordance with the current requirements, direct operating current [7] shall be applied to all IR 35 - 750 kV. The source of direct current is the accumulator battery (AB), which operates with the charge-charging unit in the constant recharge mode.

Calculation of substation lightning protection

In order to protect the building and structure of the substation with a sufficient degree of reliability from direct lightning strikes, it is necessary to use protective lightning rods.

There are two types of lightning bolt: they distinguish between rod and cable. Rods are used to protect against direct lightning strikes in buildings, and cables are used to protect power lines, it is the rod type that will be chosen when designing lightning protection for our PS.

Lightning protection calculation consists in definition of protection areas, types of protection and parameters. The lightning protection type may be as follows:

- single-core;

- two-rod of the same or different height;

- multiple rod.

When protecting an object with the simplest lightning rods (single rod, single cable, double rod, double cable, closed cable), the dimensions of lightning rods can be determined using the protection zones specified in the standard.

Conclusion

Based on the results of the course project, an 110/10 kV electric lowering substation was calculated and designed using standard electrical solutions. The necessary technological solutions were calculated and selected when designing the electrical part of the lowering substation, namely: the type, number and power of power transformers were chosen; selected an electrical connection scheme; calculations of short-circuit currents were made; high-voltage equipment for HV and LV side is selected; lightning protection of the substation is calculated. The following is a list of the final technical solutions that were used in the design of the PS:

1. TRDP power transformer 32000/110/10;

2. Vacuum BPC110 switch;

3. Current transformer TOGF110;

4. RGP SESCH-110/1250 disconnector;

5. KPU cell - KU10S;

6. Selection of operating current;

7. Selection of measurement system;

8. Double rod lightning bolt.

План-разрез подстанции.cdw

Электрическая схема принципиальная.cdw