Implementation Of A 132/33kV Transmission Substation

ABSTRACT

A substation receives electrical power from generating station via incoming transmission line and delivers electrical power through feeders and this is used for controlling the power on different routes. Substations are integral part of a power system and form important part of transmission and distribution network of electrical power system. Their main functions are to receive energy transmitted at high voltage from the generating stations, reduce the voltage to a value appropriate for local distribution and provide facilities for switching some sub-station are simply switching stations different connections between various transmission lines are made, others are converting sub-stations which either convert AC into DC or vice-versa or convert frequency from higher to lower or vice-versa. The various circuits are joined together through these components to a bus-bar at substation. Basically, sub-station consists of power transformers, circuit breakers, relays, isolators, earthing switches, current transformers, voltage transformers, synchronous condensers/ capacitor banks etc. This mini project covers the important equipments & their function in a sub- station. And also an attempt is made to cover the general maintenance of substation and checks the observations to be made for 132/33Kv transmission substation.

LIST OF ABBREVIATIONS

EHV –Extra High Voltage

SLD – Single Line Diagram

PT – Potential Transformer

CT – Current Transformer

HVCT – High Voltage Current Transformer

LVCT – Low Voltage Current Transformer

CVT – Capacitor Voltage Transformer

LA – Lightening Arrestors

ES – Earth Switches

CB – Circuit Breaker

HV side – High Voltage Side

LV side – Low Voltage Side

PLCC – Power Line Carrier Communication

OLTC –On load Tap Changer

HG Fuse -Horn Gap Fuse

OTT –Oil Temperature Indicator

WTI – Winding Temperature Indicator

IDMT Characteristics – Inverse Definite Minimum Time Characteristics.

TABLE OF CONTENTS

COVER PAGE

TITLE PAGE

APPROVAL PAGE

DEDICATION

ACKNOWELDGEMENT

ABSTRACT

CHAPTER ONE

1.0      INTRODUCTION

1.1      BACKGROUND OF THE PROJECT

• AIM/OBJECTIVE OF THE PROJECT
• SCOPE OF THE PROJECT
• FUNCTIONS OF SUBSTATION

CHAPTER TWO

LITERATURE REVIEW

• OVERVIEW OF THE SUBSTATION
• TYPES OF SUBSTATIONS
• HISTORICAL BACKGROUND OF ELECTRIC POWER TRANSMISSION
• DESRIPTION OF ELECTRIC POWER TRANSMISSION
• SUBSTATION CONSTRUCTION CONSIDERATION

CHAPTER THREE

METHODOLOGY

• DESIGN LAYOUT OF 132/33 KV, 200 MW SUB-STATION
• ASSUMPTIONS
• DESIGN OF EARTH-MAT
• DESIGN OF BUS BARS
• INSULATORS
• CIRCUIT BREAKER
• RELAYS
• CURRENT TRANSFORMER
• POTENTIAL TRANSFORMER
• LIGHTNING ARRESTER
• SWITCHGEAR
• POWER TRANSFORMER
• CONTROL CABLE

CHAPTER FOUR

RESULT ANALYSIS

• DESIGN OF CONTROL AND RELAY PANEL COMPLETE WITH PROTECTION FOR 132/33 KV SUB STATION
• 132/33KV AUTOTRANSFORMER PROTECTION
• 132KV TRANSFER BUS BAY PROTECTIONS

CHAPTER FIVE

• CONCLUSION
• REFERENCES

CHAPTER

1.0                                              INTRODUCTION

The present-day electrical power system is A.C. i.e. electric power is generated, transmitted and distributed in the form of alternating current. It is delivered to the consumers through a large network of transmission and distribution. At many places in the line of the power system, it may be desirable and necessary to change some characteristic (e.g. voltage, A.C. to D.C., frequency, Power factor etc.) of electric supply. This is accomplished by suitable apparatus called sub-station. For example, generation voltage (33KV) at the power station is stepped up to high voltage (say 132KV) for transmission of electric power. The assembly of apparatus (e.g. transformer etc.) used for this purpose is the sub-station. Similarly, near the consumer’s localities, the voltage may have to be stepped down to utilization level. This job is again accomplished by a suitable apparatus called ‘substation.

1.1                           BACKGROUND OF THE PROJECT

The work designated to the students was to implement a 132KV/33KV EHV sub-station. Any sub-station which handles power at over 33KV is termed as extra High Voltage sub-station by the rules implemented by Indian government. The design process of an EHV sub-station begins with very elemental work of selection of site and estimation of requirements which includes capital and material. It is also needed to keep in mind, the civil aspects of a sub- station design. In India about 75% of electric power used is generated in thermal and nuclear plants, 23% from mostly hydro station and 2% comes from renewable and other resources. The distribution system supplies power to the end consumer, while the transmission system connects between the generating stations and distribution system through transmission line. The entire network forms a power grid and each power grid across the country is interconnected which facilitates uninterrupted supply.

While designing a power grid the following aspects must be taken into consideration:

• Low capital
• Reliability of the supply
• Low operating cost
• High efficiency
• Low cost of energy
• Simplicity of
• Reserve capacity to meet future requirements

Starting from the generating stations to the end users, voltage is needed to be stepped up and down several times in various substations. This ensures efficient transmission of power, minimizing the power losses. Our project is to implement a 132KV/33KV EHV sub-station where the incoming power is received at 132 KV from a generating station. The power factor is corrected here and the voltage is stepped down to 33KV and power is then transferred to distribution system of the grid to meet the requirements of the end consumers at their suitable voltage.

1.2                       AIM / OBJECTIVES OF THE PROJECT

The main aim of this project is to implement a 132KV/33KV EHV sub-station where the incoming power is received at 132 KV from a generating station. The power factor is corrected here and the voltage is stepped down to 33KV and power is then transferred to distribution system of the grid to meet the requirements of the end consumers at their suitable voltage.

At the end of this work students involved shall be able to become familiar with the functions of substation and components that made it up in power system.

1.3                                   SCOPE OF THE PROJECT

A substation may be defined as an assembly of apparatus, which transforms the characteristics of electrical energy from one form to another form. At generation stations the electric power is produced at low voltages. The electric power should not be transmitted at these low voltages due to large amount of line losses and economical reasons. To minimize the losses and for economical transmission the low voltages are stepped up to high voltages and transmitted to far off place. The consumers do not use such higher voltages directly and so they must be transformed to low voltages for distribution purpose and done in these substations .So the substation may be called as link between generation stations and consumers. The transmission voltage used in this work is132KV. The distribution voltage used is 33KV.

1.4                               FUNCTIONS OF SUBSTATION

Substation present in the power system performs various operation depend of the area of application such as stepping up the voltage, stepping down the voltage, high voltage transmission, and switching station to route the power to desire load centre.

Substation converts frequency from higher and lower and vice-versa. It also switches “ON” and “OFF” the power lines, known as switching operation.