IN-PLANT TRAINING

A

PROJECT REPORT

ON

“IN-PLANT TRAINING AT SUBANSIRI LOWER H.E. PROJECT, NHPC GERUKAMUKH, ASSAM”

SUBMITTED FOR

THE FULFILLMENT OF

BACHELOR DEGREE IN ELECTRICAL AND ELECTRONICS

GUIDED BY:                                              SUBMITTED BY:

ER. NILIM SONOWAL                                      MR. SUSEN PEGU

Assistance Manager (E & C)                              BE (EX) 4^TH Semester

MILLENNIUM INSTITUTE OF TECHNOLOGY & SCIENCE

RGPV, BHOPAL

YEAR 2011

ACKNOWLEDGEMENT

It gives me immense pleasure to present this project report on “IN-PLANT TRAINING” carried out at SUBANSIRI LOWER H.E. PROJECT, NHPC GERUKAMUKH, ASSAM in fulfillment of under graduate course B.E.

I take this opportunity to place on record my grateful thanks and gratitude to all those who have gave me valuable advice and input for my study could not have been completed if I had not been able to get the reference material from the company.

I would be failing in my duty if I do not express my deep sense of gratitude to Er. Nilim Sonowal, AM (E&C) without his guidance it would not have been possible for me to complete this project work.

                                                                                                                                                                    

DECLARATION

          I SUSEN PEGU student of B.E. 4^TH Semester from Millennium Institute Of Technology & Science, Bhopal declare that the project work entitled  “IN-PLANT TRAINING AT SUBANSIRI LOWER H.E. PROJECT, NHPC GERUKAMUKH, ASSAM” was carried out by me in the fulfillment of BE program under the university of Bhopal.

        This project was under taken as a part of academic curriculum according to the university rules and norms and it has not commercial interest and motive. It is not submitted to any organization for any other purpose.

                               

SUSEN PEGU

                             

 BE (EX) 4^TH   semester

PREFACE

The training provides an opportunity to a student to demonstrate application of his/her knowledge skill and competencies required during the technical session. Training also helps the student to develop his/her skill to analyze the problem solution, to evaluate them and to provide feasible recommendation on the provided data.

Although I have tried my best level best to prepare this an error free report every effort has been made to offer the most authenticate position with accuracy.

                                                               

                                                                            

                                              INDEX

 Sl.NO.               TITLE                                                         

1.                                 INTRODUCTION                                                                 

2.                                 SINGLE LINE DIAGRAM                                 

3.                                 GAS INSULATED SWITCHGEAR                                  

4.                                 D C SYSTEM                                                    

5.                                 DIESEL POWER HOUSE                                  

6.                                 33/11 kV SUBSTATION

 

7.                                 Alternator

8.                                 VSAT SYSTEM

9.                                 EPABX SYSTEM

10.                            WALKIE-TALKIE       

11.                            CONCLUSION

1.   INTRODUCTION

Subansiri Lower H.E. Project is the biggest hydroelectric project undertaken in India so far and is a run of river scheme on river Subansiri. The project undertaken by NHPC Ltd. is located at the Dhemaji in Assam and Lower Subansiri in Arunachal Pradesh. The estimated annual energy generation from the project is 7421MU in a 90% dependable year.

RIVER SUBANSIRI

One of the tributaries of the river Brahmaputra, river Subansiri runs through Tibet before entering contributes 11% of the total flow of Brahmaputra. It has alluring opulence of natural beauty enhance by majestic green mountain slopes on either side. After the confluence with the Kamla river, the river Subansiri gets bigger and faster.

PROJECT LOCATION

Subansiri Lower H.E. Project (2000MW) is located in Dhemaji & Lower Subansiri district in the state of Assam and Arunachal Pradesh respectively. The left abutment of the dam is in the state of Assam and right abutment of dam, Power House, Head race tunnels, Tails race channels etc. in Arunachal Pradesh. The project headquater is at Gerukamukh, district Dhemaji, Assam, which is situated at the distance of 16 km from Gogamukh, a roadside town on National Highway-52 Gogamukh is about 455km from Guwahati & 44 km from Dhemaji & 40 km from North Lakhimpur both districts headquarters of Assam

SALIENT FEATURES

1.   LOCATION

STATE	Arunachal Pradesh/Assam
DISTRICT	Lower Subansiri/Dhemaji
RIVER	Subansiri

                               

2.   DIVERSION TUNNELS

NUMBER	5 Nos
SIZE	9.5m dia
SHAPE	Horse-shoe shaped
LENGTH	491 to 688 cm, total length 2940.5m
DIVERSION FLOOD	4550 cumec

3.   DAM

TYPE	Concrete Gravity
TOP ELEVATION	El 210m
HEIGHT of DAM above RIVER BED LEVEL	116m
DEEPEST FOUNDATION LEVEL	128m

4.   HRT INTAKES

INVERT LEVEL	EL 160.0 m
NUMBER	8 Nos
SIZE OF GATE OPENING	7.3 X 9.5 m
TRASH RACK	Inclined type
Nunber of BAYS	2 Nos
Size	7.5m X 23.75m with central pier 2.5

5      . HEAD RACE TUNNELS

NUMBER	8 Nos
SIZE	9.5m dia
SHAPE	Horse shoe
LENGTH	From 608m to 1168m
TOTAL LENGTH	7128m
DISCHARGE (DESIGN)	322.4 cumec

                               

6. PRESSURE SHAFT

NUMBER	8 Nos
SHAPE	Circular / horse shoe
SIZE	8m dia
LENGTH	192m to 215m (incl. steel line portion of 155m)

                                7. POWER HOUSE

TYPE	Surface
INSTALLED CAPACITY	2000 MV
NO. OF UNITS	8 nos each of 250 MV
SIZE	285m X 61m X 64m
TYPE OF TURBINE	FRANCIS
OPERATING GROSS HEAD	91m

                                8. HYDROLOGY

CATCHMENT AREA	34900 sq km
LOCATION OF CATCHMENT	Lat: 27˚ 3’15’’N , Long: 94 15’30’’E
AVERAGE ANNUAL BASIN RAINFALL	2356 mm
AVERAGE ANNUAL RAILFALL (DAM)	4600 mm
AVERAGE TEMPERATURE:    -maximum -minimum	-31.15C 7.85C
OBSERVED DISCHARGED -maximum -minimum	-12940C -188 cumec

                                9. RESERVOIR

MAX RESERVOIR LEVEL	EL 208.5m
FRL	EL 205.0m
MIN RESERVOIR LEVEL	EL 190.0m
GROSS STORAGE FRL	1365m cum
SUBMERGENCE FRL	34.36 sq. km

2. SINGLE LINE DIAGRAM

 Single Line Diagram is the simplified representation of power system components with each other, with each component represented by its symbol.

The single line diagram of the generator 420 kV GIV & potyard & 145 kV GIV & potyard of the Subansiri Lower H.E. Project.

3.   GAS INSULATED SWITHCHGEAR

A typical GIS arrangement consists of a circuit breaker, disconnecting switch, earthing switch, bus bar, voltage transformer and lighting arrester. In SLP SF6 will be employed as the insulating gas because of its excellent properties. Gas sections are used as spacers in order to minimize the range of trouble, allow for prompt repair and monitor the gas effectively.

SLP will have 145 kV and 420 kV GIS. The single line diagram shows both.

A.   420 kV GIS

-        SPECIFICATION

Sl. No.	Parameter	Unit	Data
1.	GENERAL
	Manufacturer		Areva T&D
	Type		T155
	Place of manufacture		Aix les bains (France)
	Number of sections in GIS		2
	Scheme		Double bus bar
	Number of generator bays		8
	Number of line bays		6
	Number of power transformer bays		2
	Number of bus coupler bays		2
	Total number of bays		18

GENERATOR BAY

2.	Surge Arrestor
	Type		Gapless metal oxide station type
	System voltage	kV	420
	Rated voltage	kV	336
3.	Disconnector
	Type		3 separate pole mechanically coupled and group-operated
	Operation		Motorized as well as manual
4.	Circuit breaker
	Type		SF6
	Rated continuous current	A	4000
5.	Enclosure
	External diameter	mm	540
	Internal diameter	mm	528
	Conductor
	External diameter	mm	190
	Internal diameter	Mm	181

(i)                          PURPOSE OF THE DOCUMENT

The purpose of this design memorandum is to define for 420 kV GIS, the following:

·       Design philosophy

·        System description

·        Input parameters for design

·        Standard and codes

·        Design and selection criteria

·        Equipment data

·        Material specification

·        Major technical features

·        Basic arrangement and single line diagram.

(ii)                     DESIGN PHILOSOPHY AND SYSTEM DESCRIPTION

·       GENERAL CONSIDERATION

 The switchgear has double bus bar arrangement. Eighteen bay 420 kV SF6 gas insulated switchgear (excluding VT bays) are installed between A-line and B-line of powerhouse at EL 124.50M. The GIS is divided in two separate sections each of 9 bays. Each section of GIS has four generator bays, three line bays, one power transformer bay and one bus coupler bay. Each section of GIS is normally operated independently by sectionalizing each bus through a double disconnector.

Each bus is capable of evacuating full capacity generated by Subansiri Lower Power Station including overload and future Lilo power of approximately 1500MW.

Our modular concept include

Possibility to remove and replace the fully assembled parts of circuit breaker

Maintenance of one busbar with the other in service Interchangeability of similar parts

Future extension of bays without shut down of power plant.

·        SPECIAL CONSIDERATION

    GIS is subdivided into the following separated monitored zones:

·       Each circuit breaker

·       Each termination with feeder disconnector

·       Each bus section with corresponding bus bar disconnector

·       Voltage transformers

·       Surge arrestors

·       Each zone is furnished with gas density monitoring device. The gas insulated bus duct enclosures are the Aluminium alloy materials.

·       Windows for viewing physical status of switches.

·        MAIN RATING

Rated voltage, kV	420
Rated frequency, Hz	50
Rated withstand voltage to earth: -power frequency, kV -lightening impulse(peak value),kV -switch impulse, kV	520 1425 1050
Rated short-time withstand current, kA (rms)	63 for 1 sec
Rated peak withstand current, kA	157.5
Rated normal current, A (rms)	4000

·       PERPORMANCE CRITERIA AND GUARANTEE

  The equipment/components of GIS along with all auxiliaries and accessories are capable of performing intended duties under specified condition and as per clause 9.4 of PTS of vol II A.

·       DESIGN AND CONSTRUCTION

All mechanical parts, which are outside of gas filled compartments, are externally accessible without disconnecting the main bus bar or feeder circuits.

All current carrying components of the equipment are capable of continuous operation at the specified rated current without exceeding the maximum temperature rises specified in the relevant IEC standards.

·       ARRANGEMENT AND ASSEMBLY

The arrangement is single-phase enclosed. The assembly consists of completely separate pressurized section designed to minimize the risk of damage to personnel or adjacent sections in the events of a failure occurring within the equipment. Rupture diaphragms are provided to prevent the enclosures from uncontrolled bursting and suitable deflectors provided to prevent the enclosures from uncontrolled bursting and suitable deflectors provide protection for the operating personnel.

B.                        145 kV GIS

-        SPECIFICATION

Sl. No.	Parameter	Unit	Data
1.	General
	Location		Row-A & Row-B &EL 124.50
	Number of power transformer bays		2
	Number of station transformer bays		2
	No. of line bays		2
	No. bus coupler bay		1
	Switchgear arrangement		Double bus bar
	Seismic level		0.19g DBE
2.	Design		B65
	Rated nominal voltage Un	KV	132
	Rated highest voltage Um	KV	145
	Rated frequency	Hz	50
	Rated normal current
	-feeder bays	A	2000
	-bus coupler bays	A	2000
	-bus bars	A	2000
	Annual gas loss	%	<0.5 Vol. %
3.	High voltage circuit breaker
	Type		B65-CB
	1-pol operated bay =E01; =E02; =E03; =E05; =E06; =E07; =E08
	Rated symmetrical short circuit breaking current Ia	kA/s	40
	Rated of rise	kV/µs	2
	First pole to clear factor		1.5
	Breaking time	s	0.050-10%
	Closing time	s	0.110-10%
4.	Disconnector
	Type		B65 DS
	OPERATING MECHANISM
	Type		B65-ME
	Writing diagram		47.010.231-02
	Heating system
	-voltage	V AC	240 50 Hz
	-rating	W	12W
5.	Surge arrester
	GIS type		B65
	Arrester type		PSB 120 F-CLASS 4
	Rated voltage of arrester Ur	kg	125
6.	Enclosure (CENELEC)
	-Inner dia.	mm	380
	-thickness	mm	8
	-approx. height	mm	1505
	-approx. weight (without gas)	kg	96.5
	-approx. weight of gas	kg	8.4

·       PURPOSE OF THE DOCUMENT

The purpose of this design memorandum is to define for 145 kV GIS, the following:

·       Design philosophy

·       System description

·       Input parameters for design

·       Standard and codes

·       Design and selection criteria

·       Equipment data

·       Material specification

·       Major technical features

·       Basic arrangement and single line diagram.

·       DESIGN PHILOSOPHY AND SYSTEM DESCRIPTION

(i)                         GENERAL CONSEDERATION

The switchgear has double bus bar arrangement seven bay, excluding VT Bays 145kV SF6 gas insulated switchgear are installed between ROW-A and ROW-B of the power house at EL+124.50

The complete GIS has two power transformer bays, two station transformer bays, two line bays and one bus coupler bay. Our modular concept includes:

·       Possibilities to remove and replace the fully assembly parts of circuit breaker.

·       Maintenance of one bus bar with the other on service

·       Interchangeability of similar parts

·       Future extension of bays without shut down of power plant

-        SPECIAL CONSIDERATION

GIS is subdivided into the following separately monitored zones:

·       Each circuit breaker

·       Each termination with feeder disconnector

·       Voltage transformers

·       Surge arrestors

·       Each zone is furnished with gas density monitoring device.

·       The gas insulated bus duct enclosures are the aluminium alloy material.

Rated voltage, kV	145
Rated frequency, Hz	50
Rated withstand voltage to earth: -power frequency, kV -lightening impulse (peak value),kV	275 650
Rated shot-time withstand current, kA (rms)	40 for 1 sec
Rated peak withstand current, kA	100
Rated normal current, A (rms)	2000

-        MAIN RATING

-        PERFORMANCE CRITERIA AND GAURANTEE

The equipment/component of GIS along with all auxiliaries and accessories are capable of performing intended duties under specified conditions and as per clause 10.4 of PTS of Vol-II.

-        DESIGN AND CONSTRUCTION

All mechanical parts, which are outside of gas filled compartments, are externally accessible and serviceable without disconnecting the main bus or feeder circuits.

All current carrying conductor of the equipment are capable of continuous operation at the specified rated current without exceeding the maximum temperature rises specified in the relevant IEC standards.

-        ARRANGEMENT AND ASSEMBLY

The arrangement is single-phase enclosed. The assembly consists of completely separate pressurized sections designed to minimize the risk of damage to personnel or adjacent sections in the event of a failure occurring within the equipment. Rupture diaphragms are provided to prevent the enclosures from uncontrolled bursting and suitable deflectors provide protection for the operating personnel.

4.   DC SUPPLY SYSTEM

DC system of 48V and 220V will be employed for providing supply to relays, controlled system, emergency lighting, etc.

4.2      220V DC SYSTEM

415V, 50Hz AC power supply to charge sets taken from station service boards are connection to a load bus and battery banks.

        Load bus-1 connected to charger set-1

        Load bus-2 connected to charger set-2

        Load bus-3 connected to charger set-3

        Load bus-4 connected to charger set-4

Thus there are four charger sets each connected to a float charger and a boost charger.

FLOAT CHARGING MODE

·       In normal operation (availability of 415V supply to all chargers) each float charger supplies the continuous normal load to its connected load bus and trickle charging current to its associated battery bank.

·       Associated to a main DCDB (DC distribution board), on failure of any one float charger the healthy float charger supplies the total continuous normal load to both the load bus and trickle charging current to respective two battery banks

·       On failure of both float chargers of a same main DCDB, healthy float chargers of other main DCDB supplies the complete 220V DC normal continuous plant load (i.e., all 220V DC consumers connected to load bus-1 upto 4) and trickle charging current to all battery banks (i.e., battery bank-1 upto 4).

BOOST CHARGING MODE

·       In normal operation boost chargers remains off. Boost chargers are provided for initial charging of battery banks.

·       During initial charging (boost charging) each boost charger boost chargers its respective battery bank and float chargers supplies the normal continuous load to their associated load buses.

·       During boost charging if the corresponding float charger fails the battery bank instantaneously supplies load to respective load bus through its tap cell and subsequently the total battery bank.

·       A separate boost charger bus provide in each charger set. Such arrangement ensures that  any one battery bank connected to a main DCDB can be connected to a healthy boost charger corresponding to the main DCDB.

·       Corresponding to a main DCDB, the selection of chargers for boost charging of a battery bank is manual with necessary safety inter locking provided.

·       During boost charging float charger feeds the 220V DC supply to its respective load bus.

4.2 48V DC SYSTEM

 240V, 50Hz AC power supply to charger sets taken from station service loads. Each charger set is connected to a load bus and one battery bank.

·       The load bus-1 is connected to charger set-1 & battery bank-1.

·       The load bus-2 is connected to charger set-2 & battery bank-2.

Each charger panel is equipped with a float charger, a boost charger and necessary controlled and supervision equipment (circuit breaker, contactors ammeters, voltmeters and alarm indicating devices).

FLOAT CHARGING MODE

·       In normal operation each float charger supplies the continuous normal load to its connected load bus and trickle charging current to its associated battery bank.

·       On failure of anyone float charger the healthy float charger is feeding the total continuous normal load to both the load bus and trickle charging current to both the battery banks.

BOOST CHARGING MODE

·       In normal operation boost charging remains off. Boost chargers are provided for initial charging of battery banks.

·       During initial charging (boost charging) each boost charger its respective battery bank & float chargers supplies the normal continuous load to their associated load buses.

·       During boost charging if the corresponding float charger fails the battery bank instantaneous supplies load to respective load bus through its tap cell and subsequently the total battery bank.

·       A separate boost charger bus provided in each charger set. Such arrangement ensures that, any one battery bank can be manually connected to a healthy boost charger.

5.   DIESEL POWER HOUSE

Diesel Generator Power House having six generators, four are of 500kVA and two are of 320kVA.

  The single line diagram of the diesel generator power house of NHPC, Gerugamukh, Subansiri Lower H.E. Project is shown in the figure.

-        SPECIFICATION

320 kVA ALTERNATOR  (JYOTI LTD)

Alternator type.	JBA315-4-B3	SR. NO.	15944
Style No.	2PSM98-302-2	KVA	320
p.f.	0.8 lag	Speed	1500 rpm
Volt	415 V	Amp	445 A
Ambient	40˚C	Phase	3
Frequency	50 Hz	Ins. Class stator	H
Rotor	H	Weight	1085kg
Duty cycle	S1	Protection IP	23
m/c rotation looking from driving side	Clock-wise	Connection	Star

6.     33/11 kV SUBSTATION

The single line diagram of the 33/11Kv substation of NHPC, Gerugamukh, Subansiri Lower H.E. Project is shown in the figure.

7.  VSAT SYSTEM

VSAT stands for VERY SMALL APERTURE TERMINAL and refers to combined send/receive terminals with a typical antenna diameter of 1 to 3.7 m linking the central hub to all remote offices and facilities and keeping them all in constant immediate contact. VSAT networks offer solutions for large networks with low or medium traffic. They provide very efficient point-to-multipoint communication, are easy to install and can be expanded at low extra cost. VSAT networks offer immediate accessibility and continuous high-quality transmissions. They are adapted for any kind of transmission, from data to voice, fax and video.

VSAT equipment

VSAT equipment consists of two units

OUTDOOR UNIT

INDOOR UNIT

OUTDOOR UNIT

A very small aperture terminal (VSAT) is a device, also known as an earth station that is used to transmit any data to the satellite and receive satellite transmissions. The “very small” component of the VSAT acronym refers to the size of the VSAT dish antenna-typically ranging from about 0.6 meters to 3.8 meters in diameter which is mounted on roof-top, or placed on the ground. This antenna, along with the attached low-noise blocker or LNB (which receives satellite signals) and the transmitter (which sends signals) make up the VSAT Outdoor unit (ODU) which is one of main components of a VSAT earth station.

INDOOR UNIT

The second component of VSAT earth station is the Indoor unit (IDU). The indoor unit is a either a small desktop box or PC or a satellite Modern that contains receiver and transmitter boards and an interface to communicate with the user’s existing in house equipment – LANs, servers, PCs, TVs, kiosks, etc. The indoor unit is connected to the outdoor unit with the cable. The key advantage of a VSAT earth station over a typical terrestrial network connection is that VSAT are not limited by the reach of buried cable. A VSAT earth station can be placed anywhere as long as it has an unobstructed view of the satellite. VSAT are capable of sending and receiving all sorts of video, data and audio content at the same high speed regardless of their distance from terrestrial switching offices and earth stations.

The outdoor unit is connected through a low loss coaxial (IFL) cable to the indoor unit. The typical limit of an IFL cable is about 300 feet.

COMPONENTS OF VSAT

-        HUB

Hubs concentrate connections. In other words, they take a group of hosts and allow the network to see them as a single unit. This is done passively, without any other effect on the data transmission. Active hubs not only concentrate hosts, but they also regenerate signals. Content originates at the hub, which features a very large 15 to 36 foot (4, 5-11m) antenna. The hub controls the network through a network a network management system (NMS) server, which allows a network operator to monitor and control all components of the network. The NMS operator can view, modify and download configuration information from/ to the individual VSAT. Out bound information (from the hub to the VSAT) is sent up to the communications satellite’s transponder, which receives it, amplifies it and beams it back to earth at different frequency for reception by the remote VSAT. The VSAT at the remote locations send information in bound (from the VSAT to the hub) via the same satellite transponder to the hub station.