suzlon s88 wind turbine technical description

8/9/2019 Suzlon S88 Wind Turbine Technical Description

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Technical Documentation

TECHNICAL DESCRIPTION

S88-2.1 MW

Project: Standard WTG

Document Number: WD00122

Document Class: 2 [3, 4 = Confidential]

Issue: 08 [2008-09-05]

SUZLON Windkraft GmbHDoberaner Str. 115 +49 381 203578-0

18057 Rostock | Germany +49 381 203578-10

[email protected]

www.suzlon.de


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The information contained in this documentation is the property of Suzlon R&D Germany. This documentation and extracts thereof mayonly be duplicated or forwarded to third parties following explicit written approval by Suzlon R&D Germany. We reserve the right tomake changes and improvements to this documentation as well as the hardware and software features at any time and without priornotification.All product names used in this documentation are trademarks or otherwise protected by law, even if not specifically indicated.

© 2007-2008 by Suzlon R&D Germany | All rights reserved.

TECHNICAL DESCRIPTION | S88-2.1 MW

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Overview Technical Documentation

The grey marked image indicates the description which follows on the next pages.

Technical

Description

Technical Data Safety

– General Safety

– Safety in a WTG

Installation

– Mechanical– Electrical

Transportation /Package /Storage

Commissioning

MaintenanceOperation /Logbook

Troubleshooting

– Procedures

Appendix

– Check lists– Charts

– Spare Parts– Drawings

– …

SCADA

– SC-Plant Network– SC-PPC

– SC-MetStation– …

Electrical

Documentation

– Single Line Diag.

– Electr. Data andSettings

– …


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10.2 Medium voltage cabinet and transformer .....................................................................31

10.2.1 Power in tower (optional) ..........................................................................................32

11

Lightning and surge protection system.......................................... 33 11.1 Lightning protection zones.........................................................................................33

11.1.1 Rolling sphere simulation ..........................................................................................35

11.2 Lightning protection outside WTG...............................................................................35 11.2.1 Lightning rods and receptors .....................................................................................36

11.2.2 Spark gaps .............................................................................................................36 11.2.3 Lightning arrester cables...........................................................................................37

11.2.4 Nacelle ...................................................................................................................37

11.2.5 Hub construction......................................................................................................37

11.3 Lightning protection inside the WTG............................................................................38

11.4 Equipotential bonding system ....................................................................................38

11.5 Subterranean earthing system (optional).....................................................................38

12 Condition Monitoring System (optional) ........................................ 39

13 SUZLON CONTROL SYSTEM ............................................................ 40

13.1 SC-Turbine .............................................................................................................41

13.2 SC-Commander .......................................................................................................41

13.3 SC-Service Terminal (optional) ..................................................................................41

13.3.1 SC-Terminal-fixed....................................................................................................41

13.3.2 SC-Terminal-portable ...............................................................................................41

13.4 SC-Power Plant Controller (optional)...........................................................................41

13.5 SC-MetStation (optional)...........................................................................................42

14 Annotations ................................................................................... 43


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Notes on manual

1 Notes on manual

This manual is part of the Technical Documentation of a SUZLON wind turbine

generator (WTG). It describes the Technical Description of a WTG and/or wind farm.

The document is meant for authorised and qualified staff only. It has to be carefully read andunderstood before performing the tasks.

The text contains abbreviations. When used for the first time the term is written in fullnotation. The abbreviation stands in brackets behind the full notation term, e.g.: windturbine generator (WTG).

Pages, tables and figures are cross references and numbered consecutively. The documentcontains further cross references and bookmarks intended to guide the reader to moredetailed information.

Figures may come with positioning numbers explaining determined components. Thepositioning number appears again behind the explained component in the text as follows:

Dimensions and weights are given according to the "International System of Units" (SI).

Photos in this manual illustrate examples. Equipment and procedures may differ regardingthe specific projects. Therefore, the content of the photos is not to be considered asgenerally applicable. Contact the responsible logistic manager for project specificinformation.

If any suggestions or improvements are required please forward your comments [email protected].

As the SUZLON WTGs are continually improved and further developed, we reserve the rightof modifications.

Figure 3–1/5

Positioning number

Serial number

Chapter

1.1 Scope

This Manual is valid for the S88-2.1 MW WTG in following variants:

− V1/V2

− V3

− 50 Hz

− 60 Hz

− Standard Temperature Version (STV)

− SUZLON CONTROL SYSTEM (SCS)

− Tubular Tower

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mailto:[email protected]:[email protected]


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Notes on manual

1.2 Warranty

This document is based on the technical and product-specific parameters of the supplied

WTG. Nevertheless, the manufacturer reserves the right to add complementary informationto this document.

The manufacturer only accepts warranty and liability as they are defined in the "GeneralTerms of Sale and Delivery".

The manufacturer does not accept any warranties or liabilities for personal injuries ordamage to property, if they refer to one or several of the following causes:

The described product was

− damaged by "force majeure"

− used non-intendedly

− not operated according to the instructions given in the documentation

− operated after technical safeguards have been put out of service

− operated with inadmissible materials or equipment

− subject to modifications of its design, controlling and/or functionality without prior

consultation of the manufacturer

− equipped with replacement parts not supplied or approved by the manufacturer

− repaired improperly.

1.3 Copyright

The manufacturer has the copyright for this document.

Reproduction, copying, propagation or any other use by or information of a third party of thisdocumentation – whether in parts or as a whole – for competition purposes requires prior

written consent by the manufacturer.

All rights reserved.

Address of the manufacturer:

SUZLON Energy Ltd

5TH FloorGodrej Millenium9 Koregaon Park Rd.

Pune 411 001 | INDIA

www.suzlon.com | [email protected]

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Technical overview

2 Technical overview

In particular, the WTG is designed for climatic conditions described in Manual "Technical

Data". Its robust design and uniform weight distribution ensures high levels of safety,reliability and enhanced energy yields throughout its lifespan.

The power output is controlled by three different systems working together:

− SUZLON FLEXISLIP SYSTEM (SFS, see Chapter 4.3 on page 16)

− Pitch system (see Chapter 5.1 on page 22)

− SUZLON CONTROL SYSTEM (SCS, see Chapter 13 on page 40)

The main parts of the WTG have been designed in line with approved industry standards toguarantee operational safety and efficient operation.

The minimum outside temperature describes the limit to which temperature the durability of

the WTG is guaranteed during non-operating condition. The working temperature rangedescribes at which temperatures the WTG can operate by producing electrical power.

To keep the WTG in constant operation status all significant temperatures are measured, e.g.

the temperature outside and inside the WTG as well as temperatures of pitch accumulatorsand oil sump of gear box.

All highly stressed parts, which are made of steel, were investigated in terms of strength andsuitability.

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Technical overview

Figure 2-1: Main parts of the WTG

1 Rotor (with rotor blades)

2 Nacelle

3 Tubular tower

4 Foundation

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Foundation and tower

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3.1 Lift (optional)

The lift is installed inside the tower of the WTG and is meant to transport people and their

equipment up and down easily. The lift is constructed for permanent installation in onespecific WTG.

The transportation takes place by means of a pressure system with an automatic safetycontrol device. The automatic safety control device is placed on a panel inside the cabin.

The cabin is made of aluminium and is closed with a double door. Thus, the cabin allows amaximum space for transport of people and tools; additionally a fast driving tempo isguaranteed

Upward and downward travel can be controlled by an electrical control box from inside thecabin or from outside the cabin trough an open window. A lifting force limiter preventsupward travel in case of an overload of the cabin. Two guide wires on both sides of the cabin

prevent the lift from swinging.

Figure 3-2: Cabin overwiev (Example of Avanti)

1 Electrical control box

2 Cabin door

3 Cabin

[1]

[2]

[3]


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Nacelle

4 Nacelle

The nacelle consists of a cast main frame with a bolted-on girder system and a nacelle cover.

The main frame is connected to the tower via the yaw bearing. It carries the maincomponents of the WTG, shown in Figure 4-2 on page 12.

The nacelle cover is made of glass-fibre reinforced plastic (GRP) and designed in such waythat the internal components are fully protected against various ambient conditions. Thenacelle is also equipped with an on-board hoist for lifting or unloading material into or from

the nacelle (see Chapter 4.4 on page 20). There are two access hatches on top of the nacelleto provide access to the measuring instruments, the resistors of the SUZLON FLEXISLIPSYSTEM (SFS) on the roof and to the hub.

The nacelle cover is made in sandwich construction to avoid a quick cool down.

The temperature inside the cabinets is controlled by temperature sensors. The heaters areconnected directly to the grid and will be activated via thermostats.

Figure 4-1: Nacelle – exterior view with transparent displayed nacelle cover

1 Access hatch on top to wind measurement equipment and SFS resistor boxes

2 Vent

3 Access hatch on top for the hub

4 Access hatch for the on board hoist

[2] [3]

[4]

[1]

[2]

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Nacelle

Figure 4-2: Nacelle – interior view without nacelle cover

1 Top cabinets

2 Rotor lock disc

3 Drive train (see Chapter 4.1 on page 12)

4 Main frame (for mounting the drive train)

5 Yaw bearing (see Chapter 4.5 on page 21)

6 Generator (see Chapter 4.2 on page 15)

7 Girder system (for mounting the generator)

[6]

[1]

[2]

[4]

[3]

[7] [5]

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Nacelle

4.1 Drive train

The main components of the drive train are shown in Figure 4-3.

The main shaft is made of high grade heat-treated steel. On the rotor side, it is supported bythe main bearing, which is a robust spherical roller bearing. A shrink disk connects the mainshaft to the gear box (see Chapter 4.1.1 on page 13). Inside the gear box, the main shaft issupported by a cylindrical roller bearing. To reduce weight without losing strength and forguiding the hub cables, the main shaft is hollow.

Figure 4-3: Main components of drive train

1 Rotor lock disc

2 Main bearing

3 Main shaft

4 Gear box (see Chapter 4.1.1 on page 13)

5 Mechanical rotor brake (see Chapter 7.2 on page 25)

6 Coupling

7 Generator

[1]

[7] [4] [3][6] [5]

[2]

4.1.1 Gear box

The gear box (Figure 4-4 on page 14) is a compact design, single stage planetary/ multistage helical spur gear gear box that ensures the highest possible mechanical efficiency andpower. The first planetary gear stage takes up the slow rotor rotation and distributes thehigh torque input into subsequent planetary gears. High precision manufacturing and FiniteElement Methodology (FEM) calculations of the planet carrier ensures optimal loaddistribution to the helical gears. Reduced torque values and increased rotational speeds areoptimally converted to the high-speed operation of the generator.

The helical stage is responsible for a low sound power level, which is further reduced byimpact sound isolation via rubber bushings between gear box and main frame.

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The gear box is equipped with two independent oil circulations. The internal mechanical oilpump supplies the gear box with oil during idling mode.The external electrical lubrication system is for operation mode. With this system the oil isfiltered by a micro-filter and comprises an oil-cooling device rendering temperature

optimization.

The internal oil heating is equipped with heating rods. It operates when the oil sumptemperature is below freezing point.

Figure 4-4: Gear box (Example of Hansen Transmissions)

1 Gear box oil cooling

2 Inspection cover

3 Slip ring adapter

4

Valve for oil sample and oil change

5 Oil filter pump

[2]

[5] [4] [3]

[1]

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Nacelle

4.2 Generator system

The WTG is equipped with a single-fed asynchronous three-phase generator. During

operation, the stator side of the generator is permanently connected to the grid. On the rotorside, a slip ring connects the generator to the SFS (see Chapter 4.3 on page 16). Thegenerator is kept at optimum operational temperature by a robust air cooling system (seeChapter 6.2 on page 24).

An anti-condensation heating element is integrated into the generator, it is operated via theSCS.

Figure 4-5: Drawing of the generator system – transparent

1 Generator

2 Adapter to coupling

3 Generator cooler

4 Rotor terminal box (slip ring inside)

[3]

stator side /nacelle front

rotor side /nacelle back

[2]

[1][4]

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Nacelle

4.3 SUZLON FLEXISLIP SYSTEM

The SUZLON FLEXISLIP SYSTEM (SFS) is a robust generator system for WTG. It has been

developed to be cost efficient, to reduce mechanical WTG loads and to be suitable to feedelectrical energy under different grid conditions into electricity networks.

4.3.1 System description

The WTG optimises the power output from the available wind by a combination of thepitch system and the SFS, which is a generator control. The pitch system can operateover a wide wind speed range to maximise aerodynamic efficiency.

The SFS works with a single fed induction generator with slip rings. The slip of the generatoris flexible because its rotor current is being controlled by power electronic components. Slipmeans the difference between synchronous speed and actual speed of the machine dividedby the synchronous speed. This gives positive values for motor operation and negativevalues for generator operation.

Figure 4-6: Scheme of the SFS

1 Rectifier

2 Surge protection

3 IGBT-switch

[2] [3][1]

In an asynchronous machine with slip rings, the slip can be adjusted. As it is not possible tochange the natural rotor resistance, external resistors can be used additionally. That can beused to get a constant torque and respectively constant power over a wide range ofgenerator speed. In the SFS the rotor resistance can be adjusted. This is achieved byswitching on and off external resistors in the rotor circuit. The switching is controlled byopening and closing an Insulated Gate Bipolar Transistor (IGBT) in the DC link, which is

parallel to the external resistors. That leads to the same behaviour as continuous adjustment

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of the rotor resistance and so regulates the rotor current. The range which can be realisedonly depends on the capability of the rotor resistors.

The surge protection is connected in parallel to the IGBT unit. The surge protection consists

of a thyristor unit which short circuits the DC link in special faults like overvoltage andovercurrent in the rotor circuit. In this cases the current flows through the surge protectionand protects the IGBT.

4.3.2 System behaviour

The WTG is controlled via two separate systems working together:

1. The pitch regulation (see Chapter 5.1 on page 22) controls the maximum speed to givensetpoints. Below and above this setpoints the pitch angle will be adjusted. Thisregulation is comparable to the SFS control "slow". It also controls the generator speedwithout load.

2. The SFS regulates among others the power output to a defined stepoint. The regulation

is "fast" in comparison to the pitch system.

Table 4-1: Overview of the different operational states of the SFS

Operation state IGBT switchcondition

Rotor resistance Region Figure 4-7 on page 19

Cut in Permanently off Rotor resistance plusfull external resistors

0 to 100% power Switching on-off Little increase of therotor resistor, drivetrain damping

I+II

Constant nominalpower

Switching on-off Varying resistance.Rotor resistance plus

switched externalresistors

III

With an interaction of this two regulation systems the SFS has the following systembehavior:

During the cut in of the WTG the pitch regulation tries to keep the generator speed close tosynchronous speed. The IGBT is switched off. This leads to an operation characteristic with avery high slip (Figure 4-7 /A on page 19). The WTG is connected to the grid by a soft startermodule. Because of the high rotor resistance during cut in the inrush current is small.

After a successful "cut in" the pitch system gets a new setpoint, which is higher than thesynchronous speed. The SFS begins to control the rotor current and thus controls the poweroutput. Up to a rated power the SFS gives a small additional slip to the WTG to reduce loadsand power fluctuation.

When the reference current, respectively the power is reached, the SFS limits thecurrent/power output. The pitch system control ensures that the rotation speed of the WTGis within the given setpoints.


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The operation area of the system is limited by the following boundaries:

− Characteristic A is given by the external resistors on the roof

− Characteristic B is given by the natural slip of the generator

− There is a limitation to the maximum power output of the system (see Figure 4-7 /Pmaxon page 19)

There are given two additional areas between the boundaries (see Figure 4-7 on page 19,shaded areas). These areas are defined due to the losses of the external resistors and thusgiven by the power which can be overtaken permanently (see Figure 4-7 /D on page 19). Inthe left shaded area the system works continuously. The right diagonal shaded area is fordynamic operation at higher rotation speeds due to gusts. The nominal working point of theWTG is given in Figure 4-7 on page 19.

Between nominal current and maximum current is a 11.1% range left. The WTG is able toproduce 100% power also when the grid voltage is 10% lower then normal voltage becauseof a available reserve in the power electronic components. The power output of the WTG islimited to nominal power due to the mechanical loads.

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Figure 4-7: Working areas of SFS

A Characteristic with max. resistors, IGBT switched off, full external resistors are added

B Characteristic with natural slip of generator, IGBT switched on continuously, externalresistors short circuited

C Power curve

D Border between region of continuous and short-time operation. In the area left of this

line, the system can work continuously, in the area right of the line, it can work for a

short time only (e.g. for gusts).

Nominal working point of

Possible working region continuously

Possible working region for dynamic use (e.g. strong gusts)

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4.4 On-board hoist

The on-board hoist is situated inside the nacelle to lift small items into and out of the nacelle

through a bottom hatch at the rear of the nacelle. The on-board hoist is an electrical chaintype and is mounted on a frame. The rail is secured to the main frame of the nacelle coverunderneath the roof.

Figure 4-8: Position and parts of the on-bord hoist

1 Frame

2 Motor

3 Chain bag

4 Hook

5 Pendant control

6 Bottom hatch (open)

[1]

[2]

[3]

[4]

[5]

[6]

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Nacelle

4.5 Yaw system

The nacelle is mounted to the tower with a torque adjustable friction-type yaw bearing

consisting of polyamide slide bearings, which transmit the loads from the nacelle to thetower.

The bearing is of a strong, solid construction to avoid damage. All parts of the yaw bearingare manufactured with high grade steel. The yaw system is equipped with a lubricationsystem for greasing the rotating/moving yaw components. Additionally it avoids noise andvibration during yaw tracking.

The WTG uses a reliable and proven yaw system to ensure optimal alignment of the rotor tothe wind. The wind direction is sensed by two anemometers on the nacelle roof (see Chapter9 on page 28), which send the information to the controller. The yaw tracking is performedand controlled by three electrical gear motors, which are activated as soon as the systemrecognises a certain predefined difference between the rotor axis and the current winddirection. The yaw drives turn the nacelle into the wind by rotating it via a friction typebearing against a fixed gear rim sitting on the top section of the tower. A sensor located on

the gear rim registers the number of turns the nacelle performs in the given direction toavoid over twisting the cables. If the nacelle turns more than a predefined number of timesin the same direction, the WTG is temporarily shut down and automatic unwinding starts.Afterwards the WTG restarts automatically.

The system ensures with a precise yaw a high energy yield and reduces mechanical load onthe WTG caused by changes in wind direction.

Figure 4-9: Yaw system

1

Main frame

2 Yaw drives with integrated brakes

3 Gear rim

[3]

[2]

[1]

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Rotor

5 Rotor

The rotor consists of a high strength cast iron hub supporting three pitch able rotor blades.

The blades are connected to the hub via ball bearings. They can be turned with the pitchsystem (see Chapter 5.1 on page 22). The hub is directly connected to the main shaft andtransmits the rotation of the rotor via the drive train to the generator. The hub is housed in anose cone that is made of GRP and covers the hub cabinet.

The rotor blades are aerodynamically optimised to provide high lifting forces and low air-

resistance values to produce high performance. The rotor blades are made of high grade GRPand manufactured by using Resin Infusing Moulding (RIM) technology. The blades arelightweight but at the same time possess a high degree of stiffness and mechanical strength.Their low weight to diameter ratio results in low stresses on the drive train, thus enhancingthe life and efficiency of the WTG.

At their roots, the rotor blades have a flange that is bolted to the hub via double-row ballbearings. Each blade is equipped with a lightning receptor. The lightning is guided from the

receptors to the hub and thus to the rotor shaft (see Chapter 11 on page 33). From the rotorshaft, the lightning is conducted to the grounded main frame with the help of spark gaps(see Chapter 11.2.2 on page 36).

Figure 5-1: Rotor

1

Rotor blade2 Handrail

3 Exit hatch (there are 3 hatches to enter the hub – 2 are shown in figure)

4 Lightning protection

[1]

[2]

[3]

[4]

5.1 Pitch system

The pitch system has been designed with a triple redundancy, which means that each bladehas its own drive system consisting of a motor with gear box, a frequency converter and abackup system. The pitch angle of each blade is accurately adjusted to the requirements of

the SCS. With this, it is possible to turn the rotor blades more than the needed 90°. The SCS

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Rotor

transmits the required set point for the blade position, which is controlled for each bladeseparately by the respective frequency converter.

The pitch system operates in the following way: Below nominal wind speed, the pitch angle is

constant at 0° position. Once the wind speed reaches nominal speed, the pitch regulationstarts to regulate the pitch angle to limit the rotational speed of WTG to the nominal speed.In comparison to the SFS this regulation is "slow".

Each pitch drive has its own battery backup to ensure its functionality, even when theelectrical grid is not available. In this case the WTG stops immediately by rotating the bladesinto feathering position with the energy of the battery backup. The SCS, which is equippedwith an uninterruptible power supply (UPS), checks the status of the backup systemsperiodicly and will shut down the WTG in case the energy of the pitch batteries drops below apredefined value.

The pitch motors are fastened inside the hub. Their drive pinions are interlocked with theinner gear wheel of the blade bearings, which supports the rotor blades. The pitch motorsare equipped with an internal brake, which holds the blade position when the pitch is not

active. To guarantee high performance the blade bearings are made of high tensile double-

row ball-bearing slewing rings. The pitch control system and the emergency battery backupsystems are located in suitable control cabinets inside the hub. The supply andcommunication cables to the nacelle are passed through the low speed hollow main shaft. Aslip ring behind the gear box transmits the electrical signals and supply from a static to arotational condition.

The pitch drive is equipped with an extra strong motor featuring with an extra highbrake down moment to deal with higher loads in case of icing. The seals for the gear and thedrive are made of special Nitrile-Butadiene-Rubber (NBR).

The pitch system is equipped with 1 heater within every battery box. It warms up theaccumulators and prevents humidity inside the boxes. The heating is operated bythermostats, which are integrated in the battery boxes. A temperature sensor is installed ineach battery box. It will shut down the WTG safely in case of low temperature.

Figure 5-2: Hub without blades; view into the pitch system

1 Pitch drive

2 Pitch bearing

3 Pitch cabinet

[3]

[2]

[1]

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Cooling systems

6 Cooling systems

The gear box, generator and each control cabinet are equipped with cooling systems.

All cooling systems are designed in such a way, that the optimum operation temperature willnot be exceeded. The components to be cooled are monitored by a sensors system and theinformation is processed by the SCS.

6.1 Gear box cooling

The gear box (see Chapter 4.1.1 on page 13) is cooled via the oil flow that is passed throughthe oil/air heat exchanger. A thermal choke shuts off the oil circulation during start-up untilthe minimum operational temperature of the oil has been reached. An oil pump brings the oildirectly to the relevant gear box components.

Additionally, the SCS monitors the gear box temperature by means of temperature sensors

fitted to the gear box bearings and in the oil sump.

6.2 Generator cooling

The generator (see Chapter 4.2 on page 15) is cooled by two separate cooling air circuits(Figure 4-5 /1 on page 15).

The inner, closed cooling air circuit is fed by the rotor cooling ducts. Special air guidingdevices provide effective cooling of all moving parts. The air to air heat exchanger, a part ofthe stator housing, transfers the heat to the outer cooling circuit.

The outer cooling circuit has its air intake at the drive end side. One axial-flow bladed fan,located at the drive end side, sucks the air in, blows it through the axially placed coolingtubes and discharges it at the non drive end side. The cooling air for the slip ring is

introduced by an air guiding device into the slip ring housing and discharged through anopening in the bottom of the nacelle.

Additionally, the SCS monitors the generator temperature by means of temperature sensorsfitted to the generator bearings and inside the windings.

6.3 Cabinet cooling

The cabinets are cooled by a fan system.

The fans blow cool air through filters and into the cabinets. Warm air leaves the cabinets viafiltered outlets. A sensor system with programmed minimum and maximum values for thecontrol cabinet temperature switches the fans on and off on demand.

Humidity sensors activate fans and heaters if the humidity inside the cabinets reaches acertain limit.

Additionally, the SCS monitors the cabinet temperature by means of temperature sensors.

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Brake system and rotor lock

7 Brake system and rotor lock

The brake system stops the rotation of the rotor and the main shaft. It consists of two

independent systems:

− The aerodynamic brake (see Chapter 7.1 on page 25) is operated by the pitch system of

the three blades. It is used as the standard brake during automatic operation.

− The mechanical brake (see Chapter 7.2 on page 25) is an active brake only for

supporting the aerodynamic brake. It works with hydraulic pressure.

7.1 Aerodynamic brake

The aerodynamic brake is operated by pitching the rotor blades. For braking, the pitchsystem turns the leading edge of the rotor blades to the 90° position wind wards (also calledfeathering position). The rotor blades lose their lift and increase their drag, which is utilisefor braking.

The aerodynamic brake is equipped with a safety system ensuring the blades can be pitchedeven in the event of a grid failure. In this case, each pitch motor is supplied with power byan individual battery box, which delivers the necessary energy for pitching back to thefeathering position.

Each of the three blades have an independent pitch drive to ensure safe operation. Thesystem is then comprised of three aerodynamic brakes.

7.2 Mechanical brake

The mechanical brake is located on the high speed shaft between gear box and coupling.Hydraulic pressure prevents pressing the brake pads against the brake disc. It is applied by

hydraulic pressure (active brake). The brake pads are pressing against the brake disc, thusbraking the shaft.

The mechanical brake is only used to stop the WTG when it has already been decelerated bythe aerodynamic brake. That means, the mechanical brake operates at a very low rotationalspeed and hence it is used only as a parking brake while applying the rotor lock pin or inemergency case.

Figure 7-1: Mechanical brake

1 Brake pads

2 Brake disc

gear box connection(Drive End – DE)

[1]

[2]generator connection(None Drive End – NDE)

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Brake system and rotor lock

7.3 Rotor lock

The mechanical rotor lock prevents the rotor from moving during service and maintenance

work. It is fitted to provide additional personal safety when working inside the hub and onthe nacelle/hub roof.

The rotor lock disc is positioned on the main shaft inside the nacelle. The rotor lock pin islocated underneath the main bearing and is operated by the hydraulic system (see Chapter8.1 on page 27) during a standstill condition of the rotor. It is only allowed to use the rotorlock pin under certain circumstances (see Manual "Operation").

Figure 7-2: Rotor lock disc with main shaft

1 Main shaft

2 Rotor lock pin

3 Main bearing

4 Rotor lock disc

[3][2]

[1]

[4]

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Hydraulic and lubrication system

8 Hydraulic and lubrication system

There are two systems to ensure a permanent and essential operation of the separate

components and of the WTG. Both systems ensure a sufficient oil or lubrication supply for allcomponents (where needed).

8.1 Hydraulic system

The hydraulic system provides the oilpressure that is required for the mechanicalrotor brake and for applying the the rotorlock pin. It can be controlled manually byusing the brake and rotor lock buttons.Additionally it can be used to operate the

rotor lock pin by using the hydraulic hand

pump.The pressure vessel of the electric oil pumpsystem is fitted with a membrane suitablefor low temperatures.

Figure 8-1: Hydraulic aggregate

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Hydraulic and lubrication system

8.2 Lubrication system

In the WTG a couple of lubrication systems are present. There are two kinds of systems:

− Closed system or

− Opened system

The closed systems were lubricated onlyonce for the life time and closed afterwards.It is used for some kind of roller bearings inthe WTG.

For the opened systems lubricationreservoirs exist, to supply the componentsat all times. Such a system is used forexample for the yaw system (see Chapter4.5 on page 21).

Figure 8-2: Lubrication reservoirs forthe yaw system (LINCOLN)

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Wind measurement and aviation light

Figure 9-2: Aviation light with cover (optional)

1 Light

2 Cover

3 Metal rack

[1]

[2]

[3]

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Grid connection

10 Grid connection

The WTG is directly connected to the grid. The WTG needs to transform the voltage from

medium voltage to high voltage by means of a transformer. The transformer also minimizesthe electrical losses.

The WTG starts up by turning the rotor blades to an optimum blade angle, thus acceleratingthe rotor. When the generator speed has reached synchronous speed, it is connected to thegrid via a soft starter controlling the inrush current. After this, the bypass contactor switches

on and bypasses the soft starter. The generator is directly connected to the grid.

10.1 Compensation

The usable electrical power is the active power. By its technical nature, each asynchronouselectrical generator needs a certain amount of reactive power. This form of electrical powerplaces additional load on the electrical supply system, e.g. the cables. To compensate this

effect and to reduce the reactive power, the WTG has a compensation mechanism.

The reactive power required by the WTG is compensated by using a 16 step capacitor bank.The reactive power of the WTG is constantly measured during operation. Capacitors areswitched on and off according to whether or not additional capacity is needed. The individualcapacitor bank is switched according to the short-time-average-value of the measuredreactive power. If the supply system requires to much reactive power, one additional

capacitor bank is switched on. If the reactive power is too low, one bank is switched off. Thesystem always switches on the capacitor bank, which has the lowest individual operationtime and switches off the banks with the highest individual operation time.

10.2 Medium voltage cabinet and transformer

The medium voltage (MV) cabinet and the step up transformer are included in an areaoutside the WTG. Therefore a separate building is necessary. It is part of the owner to realisethe construction.

The transformer transfers electrical energy from one voltage level to another, e.g. from thegrid to the WTG or vice versa.

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Lightning and surge protection system

11 Lightning and surge protection system

The lightning protection in WTGs has to be designed in accordance with the active standard

IEC TR 61400-24 "wind turbine generator systems – part 24: lightning protection". Thestandard requires a full protection against direct lightning strikes and the effects of lightningstrikes. The lightning protection is designed according to lightning protection level I (LPL I),the highest existing level.

The lightning protection system of the WTG is divided into four main parts:

− Exterior lightning protection

− Interior lightning protection

− Equipotential bonding system

− Earthing system

11.1

Lightning protection zonesThe creation of lightning protection zones (LPZ) of the WTG was realised by national andinternational standards. An overview of the LPZ is shown in Figure 11-1 on page 34.Furthermore, the efficiency of the LPZ was tested by applying the rolling sphere simulation(Chapter 11.1.1 on page 35).

The LPZ 1 in the nacelle is realised by a meshstructure for damping the electromagneticinfluences. For the tower is used a metal tube construction. All cabinets inside the tower,nacelle and hub are classified as LPZ 2.

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Figure 11-1: Overview lightning protection zones (LPZ)

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11.1.1 Rolling sphere simulation

The lightning protection system is designedin accordance with the rolling sphere

simulation on the geometry of the WTG.

The rolling sphere simulation is used toplace and dimension the lightning rods toafford the highest level of lightningprotection against the nacelle.

During simulation the rolling sphere with aradius of 20 m is runnig across thegeometry of the WTG. To guarantee theLPZ 1 (inside WTG) and LPZ 0B (outsideWTG) the rolling sphere is not allowed tocontact a part of the nacelle or the hub butthe lightning rods. The LPZ 0B is not

endangered by direct lightning strikes.As shown in Figure 11-2 the rolling sphere

does not contact the nacelle cover but thelightning rod. Hence, the LPZ 0B isguaranteed. In case the lightning rod is notdimensioned correctly the rolling spherewould contact the nacelle cover. Hence, theLPZ 0B is not guaranteed.

Figure 11-2: Rolling sphere modell

1 Rolling sphere

2

Lightning rod

[1]

[2]

11.2 Lightning protection outside WTG

The lightning protection outside the WTG includes the following parts:

− Lightning rods at nose cone and nacelle

− Receptors at rotor blades

− Copper cables, spark gaps and carbon brushes

− Wire mesh inside the nacelle cover and metal hub construction

− Copper busbars for connection of cables and arresting devices

One task of the lightning protection outside the WTG is to avoid direct lightning strikes intothe mechanical and electrical operation systems of the WTG. A second task is to avoid theendangerment of free leading down of lightning currents. The electromagnetic field must bereduced to a LPL according to the LPZ 1 by the nacelle cover.

The blade of the WTG includes two lightning receptors, one in the tip and one in the middleof the blade. The receptors are connected to the spark gap at the blade root, where thelightning current will be lead onto the hub construction. From there, the lightning current willbe lead over spark gaps at the rotor lock disc on an isolated arresting path to the top sectionof the tower and then into the ground.

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11.2.1 Lightning rods and receptors

The rotor blades are equipped with receptors. The receptors avoid damages of the rotorblade by a direct lightning strike.

The lightning rod on the nacelle protect the wind measurement equipment and the nacelleagainst direct lightning strikes.

11.2.2 Spark gaps

To conduct the lightning current riskless into the ground it is necessary to protect thebearings at the rotor blade and drive train by parallel current paths, which conduct and directthe lightning current. This is realised by using spark gaps at the blade bearing, in the sectionof the rotor lock disc in front of the main bearing and at the yaw bearing.

Figure 11-3: Spark gap at the yaw bearing

1 Spark gap bolt

2 Lock nut

3 Yaw base/main frame

4 Gear rim

5 Adjustable spark gap between bolt and gear rim

[1]

[2]

[3]

[4]

[5]

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11.2.3 Lightning arrester cables

The lightning current will be conducted intothe ground by using copper cables. The

cables connect the spark gaps and thelightning rods directly with the upper towershell. The connection between the towershells is bridged by three copper cablebridges at the flange. The cross section ofthe three cable bridges is identical to thecross section of the tower shells. Hence, thetower is used for conducting lightningcurrent without influences to inside installedcables and wires.

Figure 11-4: Copper cable bridge at tower section connection – interior view of the tower

1 Tower section

2 Earthing strap

3 Flange between tower sections

[1]

[2]

[3]

11.2.4 Nacelle

The glass fibre reinforced plastic (GRP) cover of the nacelle is divided into three parts. Eachpart is provided with a mesh of galvanised steel. The meshes are interconnected to eachother in order to build a Faraday cage. Furthermore, the meshes are attached to the towerby a copper cable to bleed off the lightning current.

11.2.5 Hub construction

The hub construction is made of cast iron.

All electric components have the required distance to the nose cone. So the hub complieswith the requirements for a faraday cage.

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11.3 Lightning protection inside the WTG

The lightning protection inside the WTG includes surge current arresters and surge voltage

arresters. This components are also called surge protective devices (SPDs). The SPDsprotects the electrical and electronic systems against indirect effect of the lightning, whichstrikes the WTG or the upstreamed net system.

The main advantage of the lightning protection inside the WTG is the subsequent design ofan all side protection of control systems (incoming and outgoing wires protected by SPDs).Hence, the influences to the systems can be reduced enormously.

The bottom cabinet of the WTG includes three main surge arresters, which reduce theinfluence of lightning current and surge voltage arrester by the upstreamed net system(Figure 11-5 and Figure 11-6).

Figure 11-5: Surge arrester in bottomcabinet

Figure 11-6: Surge volge arrester inbottom cabinet

11.4 Equipotential bonding system

The task of the equipotential bonding system is the potential equalisation of all metal systemcomponents like housings, handrails, ladders and cabinets.

The equipotential bonding system is based on the potential tree concept, which is especiallydesigned for the application in WTGs. The potential equalisation avoids the generation ofdangerous voltages, which can hazard people and technical systems.

The equipotential bonding system connects all metal components of the WTG. As a result,

the electric potential of all components is the same. Thus, in case of contacting two

components there is no danger of current flow for humans.

11.5 Subterranean earthing system (optional)

The subterranean earthing system connects the WTG with the transformer star point and alloutside installations. The earthing system has to avoid potential differences between theWTG and the transformer station in case of lightning strike and the safeguarding of low loopimpedance, which is necessary for a fast and safe disconnection in case of electrical failures.The subterranean earthing system is connected to the PAS busbar in the bottom of the WTG.From this point, the earthing system is designed like a grid in the sub terrain.

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Condition Monitoring System (optional)

12 Condition Monitoring System (optional)

The intention of the Condition Monitoring System (CMS) is to prevent damages and loss of

components. It can predict damages and allow a minimum time for maintenances.Additionally, it is possible to analyse damages, increase the reliability and mean timebetween failures (MTBF).

The scope of the CMS is basic diagnostic by measuring vibration at drive train componentsand automatic detection of relevant changes. Furthermore, it is possible for CMS experts in

CMS surveillance centre to diagnose damages and thus prepare instructions for operatingstaff. The analysis of damage causes may help to develop possibilities of prevention.

The CMS components are as follows:

− Measurement of vibration on drive train (main bearing, gear box, generator)

− Communication to programmable logic controller (PLC)

− Communication to CMS surveillance centre (remote control)

The CMS device is only able to recognize but not to react! On this account it is necessary tohave a CMS surveillance centre. Here the measurements of all joined WTGs are centralisedand CMS experts react accordingly.

It is possible to retrofit the CMS.

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SUZLON CONTROL SYSTEM

13.1 SC-Turbine

The SC-Turbine is the control system of a single WTG. Via different sensors and

measurements (e.g. electrical grid data, wind speed and direction, rotational speed, yaw andblade angle and component temperatures) SC-Turbine ensures safe and stable operation andpower production of the WTG. Also statistical and operational data are stored on a flashmemory.

The innovative software solution runs on a robust industrial programmable logical controller(PLC) and ensures safe and high performance of the WTG.

SC-Turbine can be monitored and controlled with the robust SC-Service Terminal or a normallaptop directly at the WTG. Also in close interaction with SC-C it is possible to communicatewith the WTG and additionally to create reports and logs of the stored data of WTGs or thewhole wind park.

13.2 SC-Commander

The SC-Commander (SC-C) is designed as a user interface to WTGs. It manages access forcustomers, service staff and other persons, according to defined access levels, to all windpark devices, such as WTGs, meteorological masts and also to SC-PPC. At the same time itcollects, stores and distributes all required data. To see the WTG status, to carry out simpleoperations like start, stop, reset and to create reports it is necessary to use SC-C. So SC-C isthe "gate" to SC-Turbine and SC-PPC.

The SC-C can be installed on any kind of operating system. The laptop/PC has to comply withthe requirements in "Hardware Specification SC-Commander".

13.3 SC-Service Terminal (optional)

With the SC-Service Terminal operation of a single WTG is possible.

13.3.1 SC-Terminal-fixed

The fixed SC-Terminal is placed in a cabinet door of the bottom cabinet. It consists ofprocessor, monitor and key pad.

13.3.2 SC-Terminal-portable

It is possible to connect a portable and compatible SC-Service Terminal to a WTG. The SC-Terminal consists of processor, monitor and key pad in a single box and can be plugged toevery WTG.

13.4 SC-Power Plant Controller (optional)

The SC-Power Plant Controller (SC-PPC) is designed to control a complete wind parkaccording to specific requirements. The wind park will be controlled as a power plant. Forexample it is possible to reduce the power output of the wind park which is in certain casesnecessary to meet the requirements of the utilities. It is also possible to stop individual WTGsto avoid shadow flicker effects at particular areas.

The software runs on a robust industrial PLC in close interaction with SC-Turbine.Visualisation and remote control of SC-PPC is possible via SC-C.

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SUZLON CONTROL SYSTEM

13.5 SC-MetStation (optional)

The SC-MetStation is introduced to provide

a detailed and correct representation ofactual weather conditions of a wind park.Additional forecasts and calculations arepossible.

The measured data are used for:

− Production forecast

− Free wind speed

− Wind direction

− Production loss calculation

− Air density calculation

− Turbulence intensity

The SC-MetStation is placed inside the windpark it belongs to.

The SC-MetStation is equipped with astandard scope of sensors, that means: oneanemometer and one wind vane. It ispossible to increase the scope of sensors upto four anemometers and four wind vanes.

The sensors are installed at hub height.

Figure 13-2: Example of a SC-MetStation

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Annotations

14 Annotations

suzlon s88 wind turbine technical description

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