detuning damper type tdd 2.3- ro - icolim 2014icolim2014.org/2014/ppt/169.pdf · - iec 61897:1998...

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FICHTNER ENGINEERING

Autori:Dr. Ing. George A. FLOREAIng. Elena MATEESCUIng. Marius OLTEANIng. Marian VÂJUIng. Marian FLOREAIng. Lauren țiu LIPAN

Detuning Damper Type TDD 2.3- RO

P & L TEHNOROB TRANSELECTRICA

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Galloping-Fenomen● A WIND-INDUCED VIBRATIONOF BOTH SINGLE AND BUNDLECONDUCTORS● DIFFERENT FROM AEOLIANVIBRATION AND WAKE INDUCEDOSCILLATION● LOW-FREQUENCY(FROM 0.1 TO 1 HZ)● LARGE VERTICAL AMPLITUDE(FROM ± 0.1 TO < ± 1 TIMES THESAG)● A SINGLE OR A FEW LOOPS OF

STANDING WAVES PER SPAN● IT APPLIES VERY LARGE DYNAMIC

LOADS TO THE STRUCTURES● IT IS A SELF-EXCITED

PHENOMENON


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Conditions for galloping: ice and wind

• GLAZE ICE, RIME ICE OR WET SNOW ON THE CONDUCTORS(THE ICE LAYER NEED NOTBE THICK)• GALLOPING CAN OCCUR WITHOUT ICE ON

RARE OCCASIONS• GALLOPING APPEARANCE (NUMBER OF

LOOPS, AND PEAK TO PEAK AMPLITUDE)

• CAN BE DIFFERENT ON APPARENTLY SIMILARCONDUCTORS WITHIN THE SAME SPAN


• MODERATE TO HIGH WIND SPEEDS• STEADY WINDS• WIND TRANSVERSE TO THELINE• OPEN EXPOSURE OF THELINE (LOW TURBULENCE)• RIVER CROSSINGS AND LINESALONG LAKE FRONTS AREPARTICULARLY SUSCEPTIBLE• CAN LAST FOR A FEW HOURSOR SEVERAL DAYS

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DAMAGE DUE TO GALLOPING

MANY GALLOPING EVENTS CAUSE NODAMAGE, BUT SEVERE ANDPROLONGED GALLOPING APPLIES MANYREPETITIONS OF HIGH LOADS WHICHMUST BE COMPARED TO THE FATIGUESTRENGTH OF THE STRUCTURES ANDCOMPONENTS

EFFECTS OF MODEST GALLOPING:● FLASHOVERS BETWEEN VERTICALLYALIGNED PHASES● CIRCUIT OUTAGES AND● BURNS OF CONDUCTORS●LOOSENED BOLTS● BROKEN HARDWARE● FATIGUED CONDUCTOR STRANDS


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DAMAGE DUE TO GALLOPING

EFFECTS OF SEVERE AND PROLONGED GALLOPING:● FRACTURED TOWER MEMBERS● COLLAPSED TOWER ARMS● CASCADES OF LINE SECTIONS

•


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CONTROL OF GALLOPING

P & L TEHNOROB

1. ANTIGALLOPING DEVICES ( IPS, TDD)

2. ICE MELTING, ICE REMOVAL, ICE PREVENTION

3. DESIGN AGAINST GALLOPING.

TRANSELECTRICA

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TDD as antigalloping device1. Mix of pendulum effect (detuning frequencies) with phase shift forcing between torsion and other movements.

2.Thus breaking energy transfer from the wind to the bundle (owing to dynamic interaction)

3.Valid for bundle only, any number of subconductors, anyline configuration.


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TDD historical background


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TDD 2.3 Ro –Design and Fabrication

P & L TEHNOROB

The structure is composed by 86 components. The mos t important parts are:

- 2 rigid spacers (pos.1), - 2 arch structural rods (pos.2), - the elastomeric damping sleeves (pos.3) ,- 2 counterweights (pos.4), - articulated lever (pos.5).

Two types of TDD 2.3- RO (RO for Romania) were manuf actured in Romania, the difference consisting of the counterwe ight masses (8.9 and 7.8 Kg). The damping of the elastomeric part w as chosen as high as possible compatible with needed torsional stiffn ess in a design which cannot be too long for installation point of view. That needed appropriate material.There have to be installed 2 or 3 pendulums on each span phase.

TRANSELECTRICA

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TDD 2.3 Ro – TESTS


Tests based on:- IEC 61897:1998 “Overhead lines –Requirements and tests for Stockbridgetype Aeolian vibration dampers”- IEC 61854: 1998 “Overhead lines. Requirements and tests for spacers”.

Concerning the reliability the fatigue tests were carried out in the case of:•0.4 Hz – 1,000,000 oscillations;•1.5 Hz – 10,000.000 oscillations;•20 Hz – 100,000.000 oscillations .

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TDD 2.3 Ro – TESTS


The damping properties of the pendulum were tested giving the damping level and the corresponding Transfer Function. The results are shown in the diagram, for the two pendulum masses and lengths.

Fig. The transfer function of the TDD (three differ ent pendulum length) following IEC 61854.

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LIVE-LINE INSTALLATION OF PENDULUM

The minimum number of staff required for this work is:� One LW foreman (team leader), authorized I.3.T;� Two (2) LW workers, authorized I.1.T on the wires;� Four (4) workers authorized I.1.T. or without LW aut horization on the ground. The method applied is “bare hand” (the worker finds h imself at the same potential as the conductive elements on which he is working).

When the works have to be done it is necessary for the equipment to be in special exploitation regime (RSE) which consists in:� Autoreclosing cancelled,� Radio or telephone links have to be established bet ween the working area and operative dispatch centre.� The reclosing of the OHL should be done manually, o nly when the LW foreman agrees.

The LW foreman has to analyze the weather conditions .The LW foreman should have on him the LW Authorizati on filled-in for the specific working area, the Technical Instructions (SMART –IT – LST 27 /2013) and the Specific Work Safety Instructions (SMART- ISSM – 27/2013), related to this work.All along the working period, the foreman has to su pervise the working team and the working area.


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LIVE-LINE INSTALLATION OF PENDULUM - The Working Procedure


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FICHTNER ENGINEERINGP & L TEHNOROB TRANSELECTRICA

LIVE-LINE INSTALLATION OF PENDULUM - The Working ProcedureA. The foreman identifies the OHL and the

tower where the work has to be carriedon. He checks the humidity level of theair, the wind speed and decides weatherthe work should be started. He ensuresthat every crewmember is wellinstructed and understood theseinstructions.

B. The crewmembers that will work on thetower are supposed to wear the electroconductive suits, anti-UV glasses,electro conductive boots, protectivehelmet, climbing system, the little rolland insulating rope.

C. The electro insulating tools are placedon the tarpaulin and on the tool’s props.Before the work starts, the rods shall besiliconated.

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The access on the wires is done, depending on the field geometry, by one of the following methods:

•Using aerial insulated platform;•Using the aluminum ladder, directly from the ground;•Using the insulated ladder, from the tower, and the trolley to go on the wires.

Once on the potential the workers will mount a yoke on the wires. Using this yoke, together with a rope block, they will take up the pendulum and will mount it on the active wires. The pendulum is guided from the ground, using insulated ropes.When the work is finished, the workers dismantle the used tools. The action is the same with the initial one, only reversed.

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TDD 2.3 - LocationP & L TEHNOROB TRANSELECTRICA

TDD1: Position : 29 % of the span length (with a pos sible shift of maximum 2%)TDD2 : Position : either 43% or 57% of the span leng th (with a possible shift of 2%)TDD3: Position 71% of the span length (with a possib le shift of maximum 2%)

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CONCLUSIONS:

Galloping of power lines remains a serious problem in some part of the world. Galloping control or prevention methods are quite d ifficult to manage and some solutions exist around the world. Romanian ‘TSO has just installed in 2013 several hu ndreds of TDD, the torsional damper and detuner developed this time in collaboration between Russia, Belgium and Romania. Owing to the up-to-date material properties and pro per design, very best physical properties of the system have been re ached and this helps to install these devices on live line 400 kV with twin bundled conductors.


detuning damper type tdd 2.3- ro - icolim 2014icolim2014.org/2014/ppt/169.pdf · - iec 61897:1998...

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