Wind turbine controller - · PDF fileTMC 3 Installation guide Table of contents 1 PURPOSE OF THIS INSTALLATIONS GUIDE

Copyright © 2013 ORBITAL A/S ORBITAL A/S

Denmark Trykkerivej 5 6900 Skjern Denmark

www.orbital.dk

Wind turbine controller TMC3 Installation guide

Author : OK

Version : 1.05

Date : 29.09.2014

TMC3

Installation guide

Table of contents

1 PURPOSE OF THIS INSTALLATIONS GUIDE ........................................................................................ 1

2 MAIN BOARD CONNECTION OVERVIEW .............................................................................................. 2

3 THYRISTORS............................................................................................................................................. 3

3.1 INTRODUCTION TO THYRISTORS ............................................................................................................. 3 3.2 THYRISTOR TYPES ................................................................................................................................ 3 3.3 CONNECTING THYRISTORS TO THE TMC3 WIND TURBINE CONTROLLER .................................................... 5 3.4 MAIN CURRENT SCHEMATICS ................................................................................................................. 7 3.5 TESTING WITH LIGHT BULBS ................................................................................................................. 11

4 CURRENT TRANSFORMERS................................................................................................................. 13

4.1 INTRODUCTION ................................................................................................................................... 13 4.2 DIMENSIONING CURRENT TRANSFORMERS FOR THE TMC3 ................................................................... 14 4.3 CONNECTING CURRENT TRANSFORMERS TO THE TMC3 ........................................................................ 16

5 CONNECTING THE VOLTAGE MEASURING INPUTS ......................................................................... 17

5.1 400 V SYSTEM .................................................................................................................................... 17 5.2 690 V SYSTEM .................................................................................................................................... 20 5.3 OTHER VOLTAGES ............................................................................................................................... 20 5.4 ORBITAL REFERENCE TRANSFORMERS USED FOR TMC-3 ..................................................................... 21

6 PT100 INPUT ........................................................................................................................................... 22

6.1 CABLE LENGTH ................................................................................................................................... 22 6.2 TESTING WITH RESISTOR ..................................................................................................................... 22

7 CAN, ORBIVIB SENSOR 2/3................................................................................................................... 22

7.1 CABLE LENGTH ................................................................................................................................... 22

8 OPERATION PANEL ............................................................................................................................... 22

8.1 CABLE LENGTH ................................................................................................................................... 22

9 ANALOG I/O ............................................................................................................................................ 23

9.1 CONNECTION OVERVIEW ..................................................................................................................... 23

TMC3

Installation guide

Author : OK ORBITAL A/S 1 of 24 Version : 1.04 Trykkerivej 5 - 6900 Skjern - DENMARK

Date : 27.08.2014 www.orbital.dk

1 Purpose of this installations guide

Guide to installing and testing the Orbital TMC-3 controller on a wind turbine electric system.

TMC3

Installation guide



2 Main board connection overview

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Installation guide



3 Thyristors

3.1 Introduction to thyristors

Thyristors in wind turbine installations are used for providing a generator soft cut in or a motor start.

The soft cut in is a method whereby the generator is connected to the grid in a smooth way to avoid high current peaks on the grid. After the generator is connected to the grid, the bypass contactor is switched on in order to prevent an overheating of the thyristors.

If the wind speed is high enough to produce power, but caused low viscosity of the gear oil or any other mechanical friction e.g. caused low temperature, a rotation of the rotor can be difficult to obtain. Here the motor start function assists to boost the rotation of the rotor as the generator now works as a motor.

The motor start forces the blades to rotate (by using power from the grid) and accelerates the rotor to a predefined RPM setting. After that the wind takes over, the rotor accelerates to the correct RPM (the cut in point) and the generator is connected to the grid.

By using thyristors during the motor start, the current extracted from the grid can be controlled and limited in order to avoid high current peaks or blowing fuses.

3.2 Thyristor types

Thyristors are manufactured in different packages/cases often called “blocks”. Typically there are 2 thyristors in one block.

Thyristors for very high currents may only contain 1 thyristor in one block.

The thyristors must be configured in “anti parallel” in order to ensure that both the positive and the negative half wave cycle of the grid can be controlled.

This is easily done at a thyristor block containing 2 thyristors by establishing a connection between terminal 2 and 3 by means of a copper bar or a wire. See Figure 3.2-1

The configuration of the control terminals of the different blocks can vary slightly, so caution must be taken when exchanging an old thyristor block with a new one.

Examples of two different thyristor types are indicated below. Terminals 4-7 represent the control terminals, which have to be connected to the TMC3 wind turbine controller. They respectively are referred as gate and cathode connections.

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Figure 3.2-1 An example of a 250 A thyristor block connected in anti parallel with a copper bar.

Figur 3.2-2 An example of a 90 A thyristor block connected in anti parallel with a copper bar.

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3.3 Connecting thyristors to the TMC3 wind turbine controller

When connecting the thyristors to the TMC3, it is extremely important that the terminals with the numbers 201, 205, 209 and 213 are connected directly to the grid. These terminals are used to supervise the grid and ensure that the ROCOF, G59, etc. requirements are respected. Subsequently they are primary used to control the thyristors.

Looking at Figure 3.2-1, it can be seen that terminals 1+7 and 2+4 are connected inside the thyristor block so either terminal 7 or terminal 4 is connected to the grid.

Either terminal 1 or terminal 2 and 3 can be connected to the grid. It depends on the most practical way of installing the thyristors inside the control cabinet.

Terminal 213 must be connected to neutral or PE/PEN.

Figure 3.3-1 The most common connection of thyristors in a wind turbine installation. The red wires symbolize the thyristor block. The terminals 201, 205, 209 and 213 are connected directly to the grid. Terminals 201-204 refer to L1, 205-208 for L2 and 209-212 for L3.

NOTE. It is not recommended to use this way of generator connection. Please see Figure 3.4-1

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Here is an example of how to connect the thyristors.

ALWAYS check the actual connections of the thyristor block (usually indicated on the side of the thyristor block)

Start by mounting the thyristors and consider what is most practical with respect to the main current and decide whether the grid side or the generator side is to be connected to terminal 1.

Assumed it is decided that terminal 1 is to be connected to the grid side and terminals 2+3 are connected to the generator side and the thyristor block is the type shown in Figure 3.2-1.

Then it can be seen that terminal 7 (K2) is connected to the grid and that this terminal must be connected to terminal 201 on the TMC3. The gate terminal of this thyristor is terminal 6 (G2) and must be connected to terminal 202 on the TMC3.

Terminal 4 (K1) is connected to the generator side and must then be connected to terminal 203 on the TMC3. The gate terminal of this thyristor is terminal 5 (G1) and must be connected to terminal 204 on the TMC3.

Do the same for phases L2 and L3.

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3.4 Main current schematics

Figure 3.4-1 Wind turbine with 1 generator. The “Series” contactor is added for safety reasons.

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Figure 3.4-2 Wind turbine with 2 generators

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Figure 3.4-3 Wind turbine with 1 generator. The thyristors are connected in series with each winding in the generator. By this the current through the thyristors is reduced by a factor of 1.73 (SQR 3)

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Figur 3.4-4 Wind turbine with 2 generators. The thyristors are connected in series with each winding in the generators. By this the current through the thyristors is reduced by a factor of 1.73 (SQR 3)

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3.5 Testing with light bulbs

Sometimes it can advisable to test the connections of the thyristors and the main current flow without connecting the generator. The thyristors could be damaged if they are connected in a wrong way when conducting high current.

By using ordinary light bulbs instead of the generator, the current through the thyristors is reduced to a few hundred milliamps.

You need 6 light bulbs to simulate the windings in the generator. 2 light bulbs are connected in series to simulate 1 winding. In a 400V system you can use 230V/60W light bulbs.

Make a motor start and observe that the light bulbs start fading up to maximum light without any flickering and that all 6 light bulbs have the same light intensity.

Figure 3.5-1 Testing with light bulbs instead of a generator. They simulate a generator connected in Delta

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Figur 3.5-2 Testing with light bulbs instead of a generator. 2 light bulbs are connected in series to simulate 1 winding in the generator.

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4 Current transformers

4.1 Introduction

Current transformers are used to measure AC currents typically in the range of 50/60 Hz. They work like ordinary transformers with a primary winding and a secondary winding. The primary winding normally consists of only 1 winding, namely the wire of the current to be measured.

Current transformers also have a transfer ratio like other transformers, and the primary winding and the secondary winding are galvanically isolated.

The VA marking on the current transformer indicates the maximum power the transformer can provide while still obtaining the rated accuracy.

The Cl marking shows the class (accuracy) of the current transformer.

There are 2 terminals referred to as S1 and S2 which are the connections of the secondary winding. The markings P1 and P2 show the direction of the primary current.

If the current flows from P1 to P2, then respectively a current will flow from S1 to S2.

A transfer ratio is marked on the current transformer e.g. 50/1A corresponding to 50, or 300/5A corresponding to 60.

Assumed we have a current transformer marked 200/1A. If the primary current is 100 A, then the secondary current is 0.5 A. The current transformer will “try” to generate 0.5 A in the secondary winding and that word “try” is another important aspect of current transformers.

When a current is flowing in the primary winding, the secondary winding may never be left open.

If the current transformer is not used, then terminal S1 and S2 have to be short cut with a wire.

In the previous example…an open secondary winding represents an infinite high impedance. The current transformer will try to generate 0.5 A and create a voltage across S1 and S2 in order to generate a current flow. As the resistance is infinite high, then according to Ohms law, the voltage also has to be very high. Finally the voltage will increase extremely resulting that the insulating of the windings will brake and finally damage the current transformer.

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4.2 Dimensioning current transformers for the TMC3

The current measurement inputs of the TMC3 are voltage inputs, not current inputs, so a resistor must be connected between S1 and S2 on the current transformer to convert the current to a voltage. See Figure 4.3-1

The maximum voltage for the current inputs is 3 Vrms.

The formula for calculating the value of the resistor is

3 Vrms * ratio

Resistor =

Inom

0,40

3 Vrms = Maximum input voltage

Inom = The nominal generator current,

ratio = The transfer ratio of the current transformer,

0,40 = 40% measure window level.

As it can be difficult to find a resistor with the exact calculated value, it will be necessary to find a resistor with a standard value (lower than the calculated) or connect 2 resistors in parallel.

The transfer ratio of the current transformer should be as high as possible in order to avoid that the power allocated in the resistor exceeds the power (VA) of the transformer.

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An example with a 300/5A current transformer as seen below.

The transfer ratio = 300/5 = 60

The chosen generator has a nominal current of Inom = 60 A.

The value of the resistor: R = ( 3 * 60 ) / ( 60 / 0,40 ) = 1.2 Ω (1.2 Ω is a standard value)

The power allocated in the resistor = 2 * 2 * 1,2 = 4,8 W. ( Inom * 2 / 60 = 2 A )

The power allocated in the resistor is greater than the maximum VA (3) of the current transformer. So this transformer is invalid.

An example with a 200/1A current transformer as seen below.

The transfer ratio = 200/1 = 200

The chosen generator has a nominal current of Inom = 60 A.

The value of the resistor: R = ( 3 * 200 ) / ( 60 / 0,40 ) = 4 Ω ( One 1,8 Ω resistor and one 2,2 Ω resistor connected in series )

The power allocated in the resistor = 0,6 * 0,6 * 4 = 1.44 W. ( Inom * 2 / 200 = 0.6 A )

The power allocated in the resistor is less than the maximum VA (3) of the current transformer.

The class of the current transformer will be 1 or 0.5. This transformer is valid.

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4.3 Connecting current transformers to the TMC3

Figure 4.3-1 The current transformers are placed at the grid connection of the control cabinet.

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5 Connecting the voltage measuring inputs

The voltage measuring inputs on the TMC3 are designed for 2.30 Vac nominal. Voltage transformers should be used to convert the grid voltages to 2.30 Vac.

The Orbital Reference Boards 414, 424 and 454 are designed for such purposes.

5.1 400 V system

In a 400 V system, voltage transformers with a transfer ratio of 100:1 should be used.

Figure 5.1-1 Connecting an Orbital Reference Board to the TMC3 in a 400 V system.

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The Orbital 454 Reference Board contains voltage transformers and current transformers on a single printed circuit board. The voltage transformers have a transfer ratio of 100:1 and the current transformers are equipped with 75Ω resistors. Maximum current is 100 A.

Figure 5.1-2 Connecting an Orbital 454 Reference board to the TMC3.

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Figure 5.1-3 Connecting the current transformers of an orbital 454 reference board.

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5.2 690 V system

In a 690 V system, voltage transformers with a transfer ratio of 173:1 should be used.

Figur 5.2-1 Connecting an Orbital Reference Board to the TMC3 in a 690 V system.

5.3 Other voltages

Orbital A/S can deliver individual voltage transformers for other voltages.

Below are some examples.

277:2.2 V

347:2.2 V

577:2.2 V

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5.4 Orbital Reference transformers used for TMC-3

Item no. Type Description

414 220 / 2.2 VAC 400 VAC + N + PE

424 400 / 2.2 VAC 690 VAC + N + PE

454 220 / 2.2 VAC 400 VAC + N + PE

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6 Pt100 input

6.1 Cable length

Max cable length: 80m.

6.2 Testing with resistor

82 Ω = -45.7°C.

100 Ω = 0°C.

150 Ω = 130.4°C.

7 CAN, OrbiVib Sensor 2/3

7.1 Cable length

Max cable length: 80m.

8 Operation panel

8.1 Cable length

RJ45 connection.

Twisted pair, max cable length: 170m.

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Installation guide



9 Analog I/O

9.1 Connection overview

TMC3

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Documents

Wind turbine controller - · PDF fileTMC 3 Installation guide Table of contents 1 PURPOSE OF THIS INSTALLATIONS GUIDE