Y00309_Northwind_100_Operations_and_Maintenance_Manual_rev_K.pdf

Rev K

NORTHERN POWER ®

WIND TURBINE

OPERATIONS & MAINTENANCE

MANUAL

Northern Power Systems 29 Pitman Road Barre, Vermont 05641

USA

Tel: 802.461.2955 Fax: 802.461.2998 www.northernpower.com support@northernpower.com

Introduction

Northern Power 100 Wind Turbine Operations & Maintenance Manual Rev K 1‐1

1 INTRODUCTION

1.1 DISCLAIMER

Information in this document is provided in connection with Northern Power Systems products and services. No license, express or implied, by estoppel or otherwise, to any intellectual property rights is granted by this document except as provided. Except as provided in Northern Power Terms and Conditions of Sale for such products and services, Northern Power assumes no liability whatsoever, and Northern Power disclaims any express or implied warranty, whether written or oral, relating to sale and/or use of Northern Power products or services including liability or warranties relating to fitness for a particular purpose, merchantability, or infringement of any patent, copyright or other intellectual property right. Northern Power products are not intended for use in medical, life saving, or life sustaining applications.

Northern Power may make changes to specifications and product descriptions at any time, without notice.

This Northern Power ® 100 Operations and Maintenance Manual as well as any software, processes or procedures described in it is furnished under license and may only be used or copied in accordance with the terms of the license. The information in this manual is furnished for informational use only, is subject to change without notice, and should not be construed as a commitment by Northern Power. Northern Power assumes no responsibility or liability for any errors or inaccuracies that may appear in this document or any software that may be provided in association with this document.

Except as permitted by such license, no part of this document may be reproduced, stored in a retrieval system, or transmitted in any form or by any means without the express written consent of Northern Power.

Copyright © Northern Power 2011. All rights not expressly granted herein are reserved.

Any other brands and/or names used herein are the property of their respective owners.

Northern Power 100 Wind Turbine Operations & Maintenance Manual Rev K 1‐2

1.2 ABOUT THIS MANUAL

Welcome to the Northern Power® 100 Operations & Maintenance (O&M) Manual. This manual applies specifically to Northern Power Systems' Northern Power 100 B model wind turbines. This manual provides instructions and drawings for electrical and mechanical systems provided by Northern Power.

Any personnel tasked with operating, monitoring, and maintaining this power system should be familiar with the complete documentation package and should have it available for reference.

Be sure to read the important safety instructions in Section 2 ‐ Safety Information.

Northern Power 100 Wind Turbine Operations & Maintenance Manual Rev K 1‐3

1.3 IN THIS MANUAL

The Northern Power® 100 Operations & Maintenance (O&M) Manual covers all aspects of the Northern Power® 100 turbine system, including operating instructions, drawings, and documentation for vendor components.

This manual is organized into the following sections:

ABOUT THIS MANUAL

Describes how this manual is organized and includes information on typographical conventions

SAFETY INFORMATION

Outlines how safety is handled throughout the manual and lists general safety precautions

TURBINE ARCHITECTURE

Includes an overall system description

SYSTEM COMPONENT DESCRIPTIONS

Describes each of the major components, includes pictures of those components and describes how the components interact with the overall system

DESCRIPTIONS OF TURBINE STATES

Includes a description of the turbine operational states

SYSTEM CONTROL

Describes the methods to interface with the wind turbine

OPERATIONS

Describes operations tasks

MAINTENANCE

Describes maintenance tasks that must be performed on the system maintenance

TROUBLESHOOTING

Describes how to troubleshoot the system

DRAWINGS AND DIAGRAMS

Includes all relevant system drawings and diagrams

VENDOR DOCUMENTATION

Includes all relevant component documentation

Northern Power 100 Wind Turbine Operations & Maintenance Manual Rev K 1‐4

1.4 TABLE OF CONTENTS

1 Introduction ................................................................................................................. 1‐1

1.1 Disclaimer....................................................................................................... 1‐1

1.2 About this Manual .......................................................................................... 1‐2

1.3 In this Manual ................................................................................................. 1‐3

1.4 Table of Contents............................................................................................ 1‐4

1.5 Typographical Conventions ............................................................................. 1‐6

1.6 Getting Help ................................................................................................... 1‐7

2 Safety Information ....................................................................................................... 2‐1

2.1 Equipment Weights ........................................................................................ 2‐3

2.2 Equipment Electrical Hazards .......................................................................... 2‐4

2.3 Equipment Heat Hazards ................................................................................. 2‐4

2.4 General Turbine Operation ............................................................................. 2‐5

2.5 Fall Hazard ...................................................................................................... 2‐5

2.6 Safety Gear Entanglement .............................................................................. 2‐6

2.7 High Magnetic Fields Inside Generator ............................................................ 2‐6

3 Turbine Architecture .................................................................................................... 3‐1

4 System Component Descriptions .................................................................................. 4‐1

4.1 Major System Functions .................................................................................. 4‐1

4.2 General System Information ........................................................................... 4‐2

4.3 Blades And Rotor ............................................................................................ 4‐2

4.4 Drivetrain ....................................................................................................... 4‐3

5 Descriptions of Turbine States ...................................................................................... 5‐1

5.1 Initialization ................................................................................................... 5‐2

5.2 Off .................................................................................................................. 5‐2

Northern Power 100 Wind Turbine Operations & Maintenance Manual Rev K 1‐5

5.3 Rotor Stopped ................................................................................................ 5‐2

5.4 System Test .................................................................................................... 5‐3

5.5 Wait ............................................................................................................... 5‐3

5.6 Motor ............................................................................................................. 5‐4

5.7 Ready ............................................................................................................. 5‐4

5.8 Active ............................................................................................................. 5‐4

5.9 Deceleration ................................................................................................... 5‐5

5.10 Service .......................................................................................................... 5‐5

5.11 Yaw State Machine ....................................................................................... 5‐8

6 System Control‐user interface ...................................................................................... 6‐1

6.1 Base Junction Box User Interface .................................................................... 6‐1

6.2 Uptower Power Controller Interface ............................................................... 6‐4

6.3 SmartView® Monitoring System ...................................................................... 6‐6

7 Operations ................................................................................................................... 7‐7

7.1 Starting Up ..................................................................................................... 7‐7

7.2 Shutting Down ................................................................................................ 7‐7

7.3 Alarms ............................................................................................................ 7‐8

7.4 Service Operation ........................................................................................... 7‐9

7.5 Fail‐safe Operation (Protection Features) ...................................................... 7‐10

8 Maintenance ................................................................................................................ 8‐1

8.1 Service State ................................................................................................... 8‐1

8.2 Electrical Lockout/Tag out Procedures ............................................................ 8‐3

8.3 Motion Locks .................................................................................................. 8‐3

8.4 Fall Restraint System ...................................................................................... 8‐7

8.5 Rotor Service .................................................................................................. 8‐8

8.6 Main Shaft Service ........................................................................................ 8‐11

Northern Power 100 Wind Turbine Operations & Maintenance Manual Rev K 1‐6

8.7 Mainframe/Rearframe .................................................................................. 8‐13

8.8 Check Subsystems ......................................................................................... 8‐14

8.9 Yaw System .................................................................................................. 8‐16

8.10 Mechanical Brake System ........................................................................... 8‐22

8.11 Bolted Connections ..................................................................................... 8‐24

8.12 Nacelle ....................................................................................................... 8‐24

8.13 Electrical systems ........................................................................................ 8‐25

8.14 Brake Pad Replacement Procedure .............................................................. 8‐28

8.15 Tower Door Air Filter Replacement Procedure ............................................. 8‐52

8.16 Northern Power® 100 Maintenance Checklists & Bolt Torque Table ............. 8‐56

9 Troubleshooting ........................................................................................................... 9‐1

10 Drawings and Diagrams .............................................................................................. 10‐1

10.1 Electrical Drawings and Diagrams ................................................................ 10‐1

10.2 Mechanical Drawings and Diagrams ............................................................ 10‐1

10.3 General Documents and Diagrams .............................................................. 10‐1

10.4 Vendor Documentation ............................................................................... 10‐3

10.5 Protective Relay Settings ............................................................................. 10‐1

1.5 TYPOGRAPHICAL CONVENTIONS

This manual uses the following typographical conventions.

Table 1‐ Typographical conventions

Element Convention Example

Drawing Italicized names of drawings provided by Northern Power

1000119

Buttons In quotation marks ‘Auto’

Northern Power 100 Wind Turbine Operations & Maintenance Manual Rev K 1‐7

1.6 GETTING HELP

If you have problems operating your Northern Power® 100, follow these steps:

See Appendix A for Troubleshooting details. Many system details are covered in this section.

See Appendix B for Drawings and Diagrams as well as Vendor Documentation.

Contact us at:

Northern Power 29 Pitman Road Barre, VT 05641

Tel: 802.461.2955, Fax: 802.461.2953 Web: http://www.northernpower.com

If you have comments, suggestions or questions about this manual, email us at support@northernpower.com

Northern Power 100 Wind Turbine Operations & Maintenance Manual Rev K 2‐1

2 SAFETY INFORMATION

IMPORTANT SAFETY INSTRUCTIONS

SAVE THESE INSTRUCTIONS

The following is a list of safety definitions and symbols noted throughout the manual and/or located on the Northern Power100 Wind Turbine. Safety symbols in the manual appear in the left‐hand column. The corresponding text appears to the right.

Refer to the Northern Power® 100 Safe Operating Procedures for additional safety information.

Table 2: Safety definitions and symbols

Symbol Definition

DANGER indicates an imminently hazardous situation, which, if not avoided, will result in death or serious injury.

WARNING indicates a potentially hazardous situation, which, if not avoided, could result in death or serious injury.

CAUTION indicates a potentially hazardous situation, which, if not avoided, may result in minor or moderate injury.

Statements used for stating instructions or for the protection of personnel or property. This statement indicates that there is a potentially hazardous situation that, if not avoided, may result in damage to the equipment.

This symbol indicates a potential electrical hazard.

This symbol indicates a potential pinching

Northern Power 100 Wind Turbine Operations & Maintenance Manual Rev K 2‐2

This symbol indicates a potential burning

This symbol indicates that safety glasses are required.

This symbol indicates a loud noise hazard and that hearing protection must be worn.

This symbol indicates that protective gloves must be worn.

This symbol indicates a potential crushing hazard from moving parts.

This symbol indicates a crush hazard from above.

This symbol indicates a chemical hazard.

This symbol indicates a burn hazard from hot surfaces.

Proper precautions must be followed by anyone operating, opening or servicing the equipment. Operators and maintenance personnel must follow all safety instructions found in this manual and in the Northern Power 100 Safe Operating Procedures manual.

Read the maintenance section and vendor documentation for specific warnings related to individual system components.

Northern Power 100 Wind Turbine Operations & Maintenance Manual Rev K 2‐3

2.1 EQUIPMENT WEIGHTS

When following safety precautions in this manual, the following equipment weights apply.

Table 3‐ Equipment weights

Equipment Mass (kg)

Blade 370

Hub 280

Generator 2,890

Brake Disk 90

Mainframe 1480

Brake Caliper 225

Yaw System 310

Uptower Electrical 450

Rotor 1400

Tower – 37 m ~14,000

Tower ‐ 30 m ~14,000

Downtower Cabinet 50

Tower Cables 180

Total Turbine System ~20,500

Northern Power 100 Wind Turbine Operations & Maintenance Manual Rev K 2‐4

2.2 EQUIPMENT ELECTRICAL HAZARDS

When following safety precautions in this manual, the following equipment electrical hazards apply.

Table 4‐ Equipment electrical hazards

Equipment Maximum voltage

DC generation Converter DC bus voltage:

900 VDC max, 780 VDC nominal

DC energy storage

DC bus during operation = 4.5 kJ reduces to under 20 J (50V) in 10 minutes following shutdown (in less than 1 second with discharge mode operating).

Always check with a meter before touching DC bus components.

AC distribution 480 VAC +10%, 120 VAC +10%

Arc‐flash hazard at controller cabinet is category 0

Arc‐flash hazard at downtower box and protective relay box is up to category 3 (site dependant)

Control system 120 VAC +10%, 24 VDC + 10%

Tower Cables Deteriorating insulation on tower cables may present lethal shock hazard to service persons climbing the tower if the main disconnect switch (DX01) on the Downtower Box is left in the ON position. Inspect cable frequently and replace if there are any signs of damage to cable jacket.

2.3 EQUIPMENT HEAT HAZARDS

When following safety precautions in this manual, the following equipment heat specifications apply.

Table 5‐ Equipment heat hazards

Equipment Maximum temperature

Generator housing ~110º C (following full‐power operation)

Northern Power 100 Wind Turbine Operations & Maintenance Manual Rev K 2‐5

Controller — converter filter inductors

~85º C

Note: Give at least 15 minutes for cool down following full‐ power operation before working inside controller.

Controller — brake resistor case

~150º C, following shutdown. Cools off rapidly but use care when working in the vicinity

2.4 GENERAL TURBINE OPERATION

Control of public access to the wind turbine ‐ The untrained public, unaware of the common hazards inherent in wind turbines, should be kept away from all known hazards, especially climbing and electrical hazards. Networked turbine remote controls must be secured with passwords, firewalls and other network protections. The tower door and any electrical equipment outside the tower should be kept locked. Access to the base of the tower must be controlled by the owner.

The wind turbine is a machine with significant rotating mass, mounted on a tower at significant height above ground level structures and people. In the event of a catastrophic failure or uncontrolled operation potential hazards to people or equipment nearby may be present.

Protections built into the turbine control system should bring it to a stop immediately, but should they fail you should attempt to shutdown the turbine remotely and keep all persons and vehicles at least 1000 feet away from the turbine if any of the following should occur:

1) Sustained rotor speed above 65 revolution per minute

2) Obvious damage to the tower, turbine or its blades

3) Unresponsiveness to remote shutdown commands

4) Unusual noise, vibration, or tower motion (some noise, vibration, and motion is normal)

2.5 FALL HAZARD

Falls from > 10 feet above ground can result in serious injury or death. Falls even though arrested by safety equipment can still result in serious injury or disability. Observe safe climbing practices.

Northern Power 100 Wind Turbine Operations & Maintenance Manual Rev K 2‐6

2.6 SAFETY GEAR ENTANGLEMENT

Be careful of safety equipment lanyards around components that can rotate. Don't allow lanyards to get caught on rotor or brake disk parts, serious injury or death could result.

2.7 HIGH MAGNETIC FIELDS INSIDE GENERATOR

The NW100 generator contains strong permanent magnets. The generator is factory sealed and should not be opened in the field. Under no conditions should magnets be removed from the generator outside of factory controlled conditions, high magnetic forces and field strength may result in injury or death.

Northern Power 100 Wind Turbine Operations & Maintenance Manual Rev K 3‐1

3 TURBINE ARCHITECTURE

The Northern Power® 100 wind turbine has the following components:

Three bladed, stall controlled, upwind rotor with rigid hub

Direct drive permanent magnet synchronous generator

IGBT‐based full power converter allowing variable speed generator operation and compliance with the UL 1741 utility interconnection standard

Redundant rotor braking: dual mechanical brakes plus an electrodynamic brake

System controller and power converter located in nacelle

Active yaw drive system with friction damping

Steel tube monopole tower

An exploded view of the Northern Power® 100 wind turbine

Figure 3‐1 ‐ Northern Power 100 Turbine Components

Tower

Service Platform

Power Converter

System Controller

Nacelle Cover

Optional Obstruction Blade

Generator

Rotor Hub

Mechanical Brake (behind generator)

Meteorological Instruments (“Met Mast”)

Mainframe

Yaw Assembly (below)

Operations

Northern Power 100 Wind Turbine Operations & Maintenance Manual Rev K 4‐1

4 SYSTEM COMPONENT DESCRIPTIONS

4.1 MAJOR SYSTEM FUNCTIONS

The ROTOR converts the aerodynamic energy in the wind to mechanical shaft torque. It also provides a lightning path from the blade tips to the main shaft.

The GENERATOR converts the mechanical shaft power to electrical power at variable frequency, and provides the reaction torque to the rotor.

The POWER CONVERTER converts the variable frequency generator output to constant frequency for feeding into the grid.

The SYSTEM CONTROLLER manages the normal operation of the wind turbine. The system controller is integrated into the power converter cabinet.

The YAW SYSTEM orients the turbine into the wind.

The BRAKE SYSTEM slows the rotor.

The PROTECTION SYSTEM is activated when the machine exceeds its normal operating limits, and takes the machine to a safe state.

The NACELLE is an aggregate of several subsystems that include:

The mainframe subsystem carries the mechanical rotor loads to the yaw system

The yaw subsystem orients the machine into the wind and transfers mechanical loads to the tower.

The nacelle cover protects the interior components (brake system, converter, yaw drive, etc)

The met mast collects wind data for turbine control and monitoring

The TOWER holds the machine up high in the wind stream and brings the mechanical loads to the foundation

The TRANSFORMER converts the converter output voltage to grid voltage.

The FOUNDATION transmits the tower base loads to the earth, and provides a path (conduit) for the electrical service, and contains features to accomplish system grounding.

Northern Power 100 Wind Turbine Operations & Maintenance Manual Rev K 4‐2

4.2 GENERAL SYSTEM INFORMATION

Refer to Northern Power® 100 General Specification A01465

4.3 BLADES AND ROTOR

The fixed‐pitch fiberglass reinforced plastic (FRP) blades capture the wind and turn the rotor shaft. The blade has an advanced root design, which is suitable for low temperature operation, and integral lightning protection is provided. The rotor hub is a Y‐shaped design with an integral shaft mounting flange. The material is a ductile iron casting. The blade bolt holes are slotted to allow for setting pitch correctly at installation. Power limiting and control is achieved using an advanced stall control technology. In a stall controlled turbine, the captured power is a complex function of the blade design, wind speed and rotor speed. The Northern Power® 100 regulates the generator speed by using the power converter to control current in the generator, which translates to torque on the generator rotor. This torque is regulated to balance the torque applied by the wind. The resulting energy is exported to the grid.

Northern Power 100 Wind Turbine Operations & Maintenance Manual Rev K 4‐3

4.4 DRIVETRAIN

Table 6‐ Drivetrain specifications

Tilt Angle 5°

Generator Type Synchronous Permanent Magnet

Generator Speed 60.0 RPM (Rated)

Generator Rating 106 kW Continuous

200° (C) Class Insulation

Main shaft Brakes 2 Spring applied, electrically released caliper brakes for E‐Stop, Parking

Hub Height 37m for 37m tower

30m for 30m tower

Maintenance Provisions Rotor, Generator, and Rearframe service crane; (optional)

500 lb. Service Hoist (optional)

Nacelle One‐piece fiberglass

Removable port side hatch for service

Removable transparent roof slot cover for service crane use

4.4.1 MAIN SHAFT BRAKE ASSEMBLY

The Northern Power® 100 uses a main shaft braking system consisting of two caliper brakes which can be motor‐applied for normal braking and are fail safe (spring‐applied) in emergency conditions. The braking system is readily serviced from within the nacelle.

The two spring‐applied, electro‐mechanically released calipers are powered by 24 VDC. They act on a 0.7 m brake disk mounted on the rear of the mainshaft.

In addition to the two mechanical brakes, the turbine includes an electrodynamic brake that is incorporated into the power converter. The turbine may be stopped under any circumstance by

Northern Power 100 Wind Turbine Operations & Maintenance Manual Rev K 4‐4 using any two of the three braking systems (i.e., one of the mechanical brakes and the electrodynamic brake or both mechanical brakes).

4.4.2 GENERATOR ASSEMBLY

The generator is an advanced permanent magnet generator with passive air‐cooling via the exposed generator housing. The generator housing contains the bearing mounts for the generator mainshaft, which serves as the rotor mainshaft in this integrated design configuration.

The generator includes an automatic bearing greasing system which allows for extended service intervals. When the greasing system requires service, it is readily performed from within the nacelle. The generator is sealed at the factory and should not be opened for any reason.

Connection of the generator electrical leads to the power converter is factory wiring, no field maintenance is required.

Figure 4‐1 ‐ Generator Assembly

4.4.2.1 CAST GENERATOR HOUSING

The stator assembly is mounted into a cast generator housing, The generator housing also contains the front bearing mounts for the generator mainshaft, which serves as the rotor mainshaft in this integrated design configuration. The generator housing and shaft assembly are designed to transfer all turbine loads to the mainframe without affecting the generator operating clearances. The cast generator housing has fins around the circumference to air cool the generator housing and the integral stator assembly.

4.4.2.2 CAST REAR GENERATOR HOUSING

Northern Power 100 Wind Turbine Operations & Maintenance Manual Rev K 4‐5

A cast rear generator housing shields the rear side of the generator, and provides mounting areas for the mechanical brakes. The rear generator housing contains the rear bearing for the mainshaft. The generator temperature monitoring sensors and the power cables exit through this cover.

4.4.3 MAINFRAME

The Northern Power® 100 mainframe is the main structural element of the tower top assembly, transmitting the rotor loads from the main shaft and bearings to the tower. The mainframe includes external service platforms for access to the rotor hub and blades. The yaw drive system is mounted into the mainframe. Other accessories such as the fire extinguisher and the optional emergency light are mounted to the inside of this frame.

4.4.4 REARFRAME

The Northern Power® 100 rearframe is the assembly bolted to the rear of the mainframe (opposite the generator). It supports the Power Controls Assembly (PCA) as well as the nacelle fiberglass cover. A hatch is built into the floor to assist with service operations. Ductwork is built into the floor of the rearframe beneath the PCA mounts to channel hot air from the PCA out of the nacelle.

4.4.5 NACELLE ASSEMBLY

The Northern Power® 100 nacelle consists of a one‐piece fiberglass enclosure bolted directly to the main and rear frames. A side hatch makes possible all service operations that cannot be carried out entirely within the nacelle. A clear port in the roof can be removed for service crane operations. The nacelle is sized so that it can be shipped, fully assembled, in a standard height ISO container.

A rectangular steel plate bolts to the top of the assembly and provides a mounting location for the lightning rod and the aircraft warning lights (if equipped).

4.4.6 METEOROLOGICAL MAST

Mounted off of the side of the nacelle is the meteorological mast which contains the meteorological instruments that measure the wind speed and yaw error. An optional obstruction light is also mounted on the nacelle’s top.

Northern Power 100 Wind Turbine Operations & Maintenance Manual Rev K 4‐6

4.4.7 YAW ASSEMBLY

Table 7‐ Yaw Assembly Specifications

General Actively Driven, Slew Bearing, Friction Damping System

Yaw Drive Electrically Driven Planetary Gearbox

The Northern Power® 100 uses an active yaw drive system to orient the turbine into the wind. A gear motor mounted to the turbine bedplate drives against the integral bull gear and slew ring which is attached to the tower in order to yaw the turbine. A wind azimuth sensor mounted on the nacelle provides the yaw command input. A friction system provides constant yaw friction to minimize low amplitude vibration of the nacelle.

4.4.8 POWER CONVERTER AND CONTROLS ASSEMBLY (PCA)

The Northern Power® 100 PCA manages all aspects of turbine operation. These tasks include environmental control, safety system operation, fault monitoring, and remote access. In addition, the PCA houses the power converter that allows the direct drive generator to supply power to the utility grid.

The main System Control Board (SCB) is comprised of two subsystems; a Digital Signal Processor (DSP), which handles the operation of the power converter, while the balance of turbine controls are handled on a separate microprocessor.

The single line diagram of the overall turbine electrical system is referenced in Appendix B‐ Drawings and Diagrams. The input section (rectifier) converts the AC output of the generator into DC energy, stored in the DC bus. The inverter then synthesizes AC sine wave current and passes power to the utility grid. The rectifier controls generator speed by modulating the electrical torque produced by the generator such that it equals the torque created by the blades and the wind. When the wind exceeds the cut‐in threshold for the turbine, power begins to flow through the generator, converter, and into the grid.

The dynamic brake subsystem serves two purposes; it applies load to the turbine for use as a braking system, and it functions as a DC bus voltage limiter during transient conditions such as high wind gusts or converter faults, thereby protecting the power converter from high voltage events.

The controller is housed in a shock mounted UL508 compliant enclosure in the rear of the turbine nacelle.

Northern Power 100 Wind Turbine Operations & Maintenance Manual Rev K 4‐7

The power converter is an open frame device that mounts in the controller enclosure. The power converter is interfaced to and receives operating commands from SCB and its interface board. The unit is designed to comply with IEEE 519 and uses air‐cooled IGBT switching devices.

The Northern Power® 100 comes factory set with a unity power factor output, but can be programmed to supply positive or negative reactive power to the utility power system. The supplied reactive power is the summation of a fixed VAR command and a power factor command.

VAR Command enables the operator to command reactive power directly by adjusting a reactive power set point in the range from –45 kVAR to +45 kVAR (at rated voltage). This method allows the operator to set the reactive power flow independently of active power output. This reactive power is available as long as the turbine is connected to an active grid and is independent of the wind level.

Power Factor Command enables the operator to command VARs based on the active power output by adjusting a power factor set point in the range from 0.90 lagging to 0.90 leading. This method allows the operator to set the reactive power flow as a fixed percentage of active power output. When the VAR Command portion is zero, this command produces a constant power factor.

The main controller is equipped with hard switches to allow safe service mode access to the nacelle as well as manual yaw and brake control. Latching emergency stop buttons are located downtower on the base box door and uptower on the PCA.

The base junction box houses a minimal set of controls that can be used to start and stop the machine, as well as trigger an emergency stop should the need arise. The tower lights are also controlled from this location.

Remote access is via Ethernet (fiber optic, category 5, or wireless, depending on site layout) to the remote PC operating Northern Power’s remote access and control software, SmartView.

Because of this double conversion process, adding a Northern Power® 100 turbine to the grid is different than adding a traditional wind turbine in this power class because the power converter isolates the generator from the grid. Traditionally, wind turbines are directly‐connected induction generators which require utility coordination due to their reactive current needs and large fault current characteristics. To the grid, the Northern Power® 100 appears as an inverter, with no reactive current requirements and a very small fault current characteristic. The Northern Power® 100 is designed to meet the UL 1741 grid interconnection standard.

Northern Power 100 Wind Turbine Operations & Maintenance Manual Rev K 4‐8

4.4.9 TOWER

The standard Northern Power® 100 tower is a multi‐section, tapered tubular steel tower. Access is gained through a door located at the tower base. An electrical junction box that contains the power and control connection points; a fused, lockable power disconnect and a basic control interface to secure the turbine for service, is installed in the tower base. Access to the nacelle is provided by an internal ladder equipped with a fall restraint system. Decks are located within the tower slightly below each joint to simplify service and assembly operations.

4.4.10 FOUNDATION

The foundation for the Northern Power® 100 typically falls into two broad categories: concrete pad or pile type. The foundation design is site specific to accommodate varying soil conditions and other factors. The customer must provide a foundation design based on loads and key dimensions provided by Northern.

4.4.11 TRANSFORMER

One transformer per Northern Power® 100 is required for connecting the turbine with the utility system. This transformer is used to match the Northern Power® 100 output voltage to the local utility voltage and to manage the safety and power quality of the electrical interface.

This transformer is typically located adjacent to the tower base on a concrete pad although site conditions sometimes dictate other solutions/locations.

Refer to the Northern Power® 100 Application Requirements document, A00298, and the Protective Relay Specification, A00293, for further details.

Northern Power 100 Wind Turbine Operations & Maintenance Manual Rev K 5‐1

5 DESCRIPTIONS OF TURBINE STATES

The Northern Power® 100 is controlled through a sequence of state changes designed to ensure safe turbine operation. State descriptions and requirements for changing states are outlined as follows:

Table 8‐ State Definitions

Turbine State Rectifier Inverter Brakes

Initialization Off Off Applied

Off Off Off Applied

Rotor Stopped Off As requested Applied

System Test Off/Test Active Applied/Test

Wait Off As required Released

Motor Motoring Active Released

Ready Ready As required Released

Active Active Active Released

Decelerate

Active Active Generator torque & motor applied mech. brakes; solenoid apply brakes if necessary

Service Disabled Disabled Manual controls

Note: Inverter “As requested” or “As required” ‐ Inverter may be Ready or Active. The Active state may be required by VAR (reactive power) support functions.

Northern Power 100 Wind Turbine Operations & Maintenance Manual Rev K 5‐2

5.1 INITIALIZATION

The turbine enters Initialization on power up. The controller will transition to OFF after boot up is complete. The initialization takes approximately 90 seconds.

5.2 OFF

In the OFF state, the turbine controller is operating, but the power converter is offline and the rotor brakes are applied. The yaw system is operational and will track the wind if the wind speed is above ~3 m/s.

If all external conditions are correct (turbine is enabled, Run/Stop/Service switch is in the Run position, up‐tower Run/Stop switch is in Run position, no Inverter faults) the controller will transition to the Rotor Stopped state.

If the base Run/Stop/Service switch is in the Service position and/or the up‐tower Run/Stop switch is in Stop, the controller will transition to the Service state.

5.3 ROTOR STOPPED

In the Rotor Stopped state, the brakes are applied but the Inverter is available to provide reactive power support (VAR support) if requested. The yaw system is operational and will track the wind if the wind speed is above ~3 m/s.

If all conditions are met to allow the turbine to operate (environmental conditions are within range, state timers have elapsed, faults are clear, etc) the turbine will transition to the System Test state after a minimum of 5 minutes.

The turbine may remain in this state if environmental conditions prohibit operation (such as wind speed is too high, or outside air temperature is too low).

If external enables (HMI, Dispatch, or Run switches) are removed, or an inverter fault occurs, the turbine will transition to the OFF state.

Northern Power 100 Wind Turbine Operations & Maintenance Manual Rev K 5‐3

5.4 SYSTEM TEST

The System Test state is setup to allow the turbine to perform several self tests. They may or may not be used on a given turbine based on the software configuration. These tests may include:

DC Bus Limiter check – This is a test to verify that the DC Bus limiter circuit is working correctly, and the discharge resistor is present. During the test, the inverter will be activated for several seconds, and a small amount of power will be discharged into the resistor.

Mechanical brake check – This test is used to verify that a mechanical brake is producing at least the minimum amount of required torque. It is performed on one brake each time the test happens. The system alternates between the A and B brake on subsequent tests.

Accelerometer check – This test is used to verify that the accelerometer is functioning properly.

Following successful completion of all configured tests, the controller will transition to the Wait state. If any test fails, the system will transition to the Decelerate state and the appropriate faults will be displayed on the HMI.

5.5 WAIT

The Wait state is the start‐up state of the turbine where the turbine is waiting for enough wind to operate. The rotor is free to rotate (mechanical brakes released) and the DC bus is charged.

The Inverter is available to provide reactive power support (VAR support) if requested.

If enough wind is available to overcome the startup torque requirements, the turbine will begin to rotate on its own. Once the rotor speed exceeds the proper set point, the turbine will transition to the Ready state.

If there is enough wind to make power, but not enough to overcome the startup torque requirements, the turbine will transition to the Motor state.

If external enables (HMI, Dispatch, or ‘Run’ switches) are removed, or a fault occurs, the turbine will transition to the Decelerate state.

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5.6 MOTOR

In the Motor state, the rectifier feeds power into the generator, accelerating the rotor. After reaching a target speed, the rotor is released to free spin and the turbine transitions to the Ready state. The Inverter is active during motoring to support the DC bus.

If external enables (HMI, Dispatch, or Run switches) are removed, or a fault occurs, the turbine will transition to the Decelerate state.

5.7 READY

In the Ready state, the rotor is spinning, but not at a high enough rate to make power. The Inverter is available to provide reactive power support (VAR support) if requested.

If the rotor accelerates (due to wind) and surpasses the cut‐in threshold, the turbine will transition to the Active state.

If the wind dies off and the rotor slows, the turbine will return to the Wait state.

If external enables (HMI, Dispatch, or Run switches) are removed, or a fault occurs, the turbine will transition to the Decelerate state.

5.8 ACTIVE

The Active state is the power producing mode of the turbine. In this state, the Rectifier and Inverter are both active, and are working with the generator to extract energy from the wind. As the wind increases, the power flow into the grid increases. The rectifier controls the speed of the generator based on predetermined optimum rotor speed vs. wind speed relationship. The inverter precisely maintains DC bus voltage by varying output current to the grid.

If the wind dies down and the rotor slows, the turbine will transition back to the Ready state.

If external enables (HMI, Dispatch, or Run switches) are removed, or a fault occurs, the turbine will transition to the Decelerate state.

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5.9 DECELERATION

The Deceleration state is used to slow the rotor to a stop by whatever means are necessary. If the Rectifier and DC Bus limiter are available (i.e. not faulted), the turbine will generally first apply the dynamic brake (electrical braking with the generator). The mechanical brakes are driven closed, but do not act until after the rectifier has already slowed the machine. The Inverter will continue to supply power to the grid if available.

If the Rectifier and Bus limiter are not available, or the turbine needs to be stopped immediately, the mechanical brakes will apply quickly (magnets release so the brakes are spring applied rapidly).

In the case of an E‐Stop, if the Rectifier and Bus limiter are available, they will contribute as necessary, while at the same time the mechanical brakes will apply rapidly, resulting in a very fast stop.

When the rotor is stopped, and the mechanical brakes are fully applied, the turbine will transition to the Rotor Stopped state, unless an Inverter fault is present, in which case the turbine will transition to the OFF state.

5.10 SERVICE

The Service state is used for when personnel are near or within the turbine. Placing the base Run/Stop/Service switch into the Service position, or placing the nacelle Run/Stop switch into the Stop position will cause the turbine to transition to the Service state. However, the Service state functions will not be available unless both switches are in the appropriate positions.

In the Service state, the turbine will not automatically yaw. There is a yaw control switch in the nacelle that is functional in service mode, and can be used to assist with maintenance tasks.

The mechanical brakes will be applied on entrance to the Service state, but may be manually controlled from the nacelle. There is a control switch for each brake, which allows them to be released independently.

Placing the base Run/Stop/Service switch into the Run position, and placing the nacelle Run/Stop switch into the Run position will allow the turbine to resume normal operation.

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State Transition Diagram

Note: All speed values (wR = rotor speed) shown are set points and are approximate.

Figure 5‐1 ‐ NW100B Turbine Control State Diagram

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Figure 5‐2 ‐ Inverter Control State Diagram

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5.11 YAW STATE MACHINE

The yaw system runs virtually independently from the turbine state machine. If the turbine is free to operate, the yaw controller is also free to operate. If the turbine is placed into service mode, an E‐Stop is pressed, or there is a yaw system fault, the yaw controller will cease automatic operation. The yaw system will also be disabled anytime the wind speed drops very low (since the wind vane is no longer accurate).

During normal operation, the turbine is in the AutoYaw Enabled state. If the wind vane indicates the turbine is more than 5 degrees off the wind axis (after a time delay), then the controller changes to the appropriate state to move the turbine towards the correct wind direction (yawing Left or yawing Right).

The yaw system also constantly tracks the turbine position. This information is used to monitor the number of cable wraps in the tower. During the course of normal operation, the tower cable will gradually accumulate twists. When the number or turns exceeds 4 in either direction, the controller takes notice:

If turn count is higher than 4 and the turbine is not making power, the brakes will apply (turbine transitions to Rotor Stopped state) and the turbine will unwind. After unwinding, the turbine will be allowed to restart.

If the turn count reaches 5, the turbine will transition to Rotor Stopped state (regardless of power production), unwind, and then be allowed to restart.

When the turbine is placed into the Service state, the yaw system is disabled. The Yaw switch in the nacelle can be used to yaw the machine ‘Left’ or ‘Right’. The turn count limit will still apply;

it will not be possible to yaw past 5 turns in either direction.

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Auto Yaw Disabled

Yawing Left

Auto Yaw Enabled

Yawing Right

Shutting Down

Unwinding Left

Unwinding Right

Figure 5‐3 ‐ Yaw State Diagram

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6 SYSTEM CONTROL‐USER INTERFACE

There are two user interfaces for the Northern Power® 100:

The Base Junction Box Interface

Uptower Controls Cabinet Interface

The interfaces are described in detail in the following sections. The Northern Power® 100 is also provided with a PC‐based data acquisition and human‐machine interface (HMI) application called SmartView®.

6.1 BASE JUNCTION BOX USER INTERFACE

Figure 6‐1 ‐ Base Junction Box Interface Diagram

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Table 9‐ Base Junction Box Interface Element Descriptions

Element Type Description

Do Not Climb Light Illuminates red when the turbine is not in Service mode. Do not climb the tower when this light is illuminated.

Emergency Stop Latching push‐ button

The “pressed” position causes the mechanical brakes to apply with full torque and the electro‐dynamic brake to apply, initiating a fast shutdown of the turbine (if running). An E‐stop fault will also be latched in the controller. Pulling on the button (clockwise twist on some models) changes the switch position from “pressed” to “released,” however the turbine will not run until the E‐Stop fault is cleared.

This fault will need to be reset at the uptower interface, or using the SmartView HMI.

Run/Stop/Service Switch

Three‐position switch

Placing this switch in Run Mode will allow the turbine to go online after any faults are cleared. The Stop position will cause the turbine to come to a halt but will not prevent the turbine from yawing into the wind. If Service mode is selected while the turbine is running, the turbine will perform a “normal” shut down, then go to Service mode, which will prevent the turbine from starting and will prevent the turbine from yawing. This provides the safety required to allow the tower to be climbed.

Tower Light Two‐position switch

Placing this switch in the ON position will turn on the tower lights.

Main Disconnect

(DX01)

Two‐position switch

This is the main disconnect which de‐energizes all of the electrical systems in the nacelle and some of the electrical systems in the base junction box. The handle must be in the OFF position to access the inside of the base junction box.

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Service Jack RJ45 Receptacle Connect to communicate with the turbine.

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6.2 UPTOWER POWER CONTROLLER INTERFACE

Figure 6‐2 ‐ Uptower Controller Interface Diagram

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Table 10‐Uptower Controller Interface Element Descriptions

Emergency Stop

Latching push‐ button

The “pressed” position causes the mechanical brakes to apply with full torque and the electro‐dynamic brake to apply, initiating a fast shutdown of the turbine (if running). An E‐stop fault will also be latched in the controller. Pulling on the button (clockwise twist on some models) changes the switch position from “pressed” to “released,” however, the turbine will not run until the E‐Stop fault is cleared.

System Ready Light

Illuminates green when all E‐Stop buttons are in the “released” position, the mechanical brake is applied, and the Service switch is in Run Mode (Base Service switch is in ‘Service’), indicating the turbine is ready to return to automatic operation (after the Base Service switch is returned to Run Mode).

Turbine On‐ line

Light Illuminates green when Turbine is operating (online/active)

Fault Light Illuminates red when a turbine fault condition is present or has occurred.

Yaw Control Three‐position, spring‐return switch

If the turbine is in Service mode, turning this switch to Left or Right will manually yaw the turbine in the corresponding direction for the duration that the switch is held in that position.

Releasing the switch will stop the turbine from yawing.(Will not function if E‐Stop is pressed or a Yaw Fault is active)

Turbine Run Two‐position switch

Placing this switch in Run Mode will allow the turbine to go on line after any faults are cleared. If Service Mode is selected while the turbine is running, the turbine will perform a “normal” shut down, then go to Service mode, which will prevent the turbine from starting while service is being performed. If the turbine is not running, it will just transition to Service mode.

Fault Reset Momentary push‐button

If the turbine is faulted, pressing this button will clear all the faults if all fault conditions have cleared. If any fault conditions are active, those faults will not be cleared and the turbine will remain in a faulted state.

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Brake A Three‐position switch

Controls Brake A while in Service mode.

Full or Fast position – applies Brake A fast

Reduced or Normal position – applies Brake A normally

Released position – releases Brake A

Brake B Three‐position switch

Controls Brake B while in Service mode.

Positions are the same as the Brake A switch