The Polytransformer 9CHLIE (*) July 1, 2005 A Multi-voltage Miguel Oliva Transformeraedie.org/9CHLIE-paper-send/PL3.pdf · · 2017-02-06Transformer description and dimensions: Nameplate

© ABB PTPR, Cordoba (Spain), M.Oliva, July 2005

The Polytransformerconcept:

A Multi-voltage Substation Power

Transformer

9CHLIEJuly 1, 2005

Miguel Oliva

(*) International Patent Pending

(*)

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1 Introduction

2 Why a single multifunctional transformer for different transmission systems?

3 The Polytransformer concept

4 Advantages and applications

5 A practical case

6 Final summary

The Polytransformer concept: A Multi-voltage Substation Power Transformer

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1 Introduction




5 A practical case

6 Final summary

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Poly-Greek prefix meaning

many : several : much :

more than one of a ...more than usual

The latin equivalent is multi-

The Polytransformer concept: Introduction

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The Swiss Army Knife


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The Swiss Army Knife:Some facts about this useful pocket multitool.

Invented by Carl Elsener in 1891: It is over 100 years old.

After the soldier's knife, which every recruit receives uponentering the army, Carl Elsener developed a new, elegantand light weight pocket knife, with six practical tools. Hecalled this new model the "Officers and Sports Knife".

After an unparalleled success story around the world, the Swiss Army Knife is even orbiting the earth as part of the standard equipment of the Space Shuttle Crew.

The knife has also been successfully proven on expeditions: in the artic ice of the North Pole; on the highest peak on earth, Mount Everest; in the tropical rain forests of the Amazon, and elsewhere.

Time and again, it has been a life saver in situations of extreme danger and great need. The New York Museum of Modern Art and the State Museum for Applied Art in Munich have selected it for their collection of excellencein design.


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Multifunctional toolLight and compact: You can carry it on your pocket.

Many tools and different applications.Useful and convenient: You never know when you may need it.

284 g, 72 functions, thousands of applications...


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1 Introduction




5 A practical case

6 Final summary


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Power transformersare one of the most important and costly components and the critical nodes in the electricity networks.

The Polytransformer concept: Why a multifunctional transformer?

In today’s competitive environment, it is imperative to assure a secure supply of electricitywith:

• Strict cost control.• Reliability.• Quality.

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Utilities have to use their existing equipment more efficiently ensuring high reliability and an adequate level of quality in the service provided.


As a consequence, there is a need of: •Increased equipment utilization.•Reduction of forced outages.•Reduction of failure rates.

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Large power transformers reliability is very important:• They are critical for the operation of the system.• Their replacement implies considerable time and cost.

Actions to optimize performance and reliability:(1) Scheduled and predictive maintenance operations:

- To determine and follow up the actual condition of the transformers.

- Minimizes incidences.- Optimises performance.

(2) Contingency planning:- Arrangements in case of a transformer failure that

results in a prolonged outage.- To mitigate risks. It includes:

•Redundant transformers.•Spare units.


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The availability of spare units is valuable especially in generating plants and important substations.Some utilities are optimising the number of spare transformers because they are questioning if the investment is economically justified.Transformer manufacturers have to provide the utilities with:

•High quality and reliable products.•Flexible solutions to support the economic justification of an investment in transformer spares.

Such justification can be strengthened proposing a:•Compact, standardized and multifunctional unit.•Minimum transport limitations.•Spare for different transformers in multiple substations.


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1 Introduction




5 A practical case

6 Final summary


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The main features of the polytransformer are:

(1)Multiple voltage ratings at the high voltage and low voltage side:

•Designed with internal taps providing different alternatives to allow connection between different transmission systems

i.e. 400 to 230kV / 400 to 132kV / 400 to 110kV / 230 to 132kV / 230 to 107kVi.e. 345 to 230kV / 345 to 138kV / 345 to 110kV / 230 to 138kV

The Polytransformer concept.

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(1)Multiple voltage ratings at the high voltage and low voltage side:

•The power rating of the transformer varies, dependingon the connection.

•On-load tap changer regulation.•Selection of alternatives by changing connections internally when the unit is prepared for shipment to a different station.

•Simple and reliable design:Because of the winding arrangement flexibility and the facility to provide different tap connections inherent to a shell form design.


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• Tertiary designed with internal taps to provide several voltage levels to match different substations needs.

i.e. 13.8kV / 24kV / 33kV

• Selection of alternatives by changing connections internally when the unit is prepared for shipment to a different station.


(3)Maximum power rating meeting the local transportation restrictions and the temperature rise limits specified by the standards.

(2)Multiple voltage ratings at the tertiary winding.

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(4)Compact design to allow the Polytransformer to be shipped to many different substations.


• All the shipping restrictions and specific limits of the local railway system are considered.

• A shell form design helped to accomplish compact shipping dimensions providing also its natural mechanical robustness to withstand transportation and hauling accelerations.

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(5)Minimum installation dimensions to optimise the substation space requirements.

• Minimizing the total dimensions allows to replace a wider range of existing transformers or to be used in substations with limited space.


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(6)Short circuit impedance of the Polytransformerdesigned taking into consideration the impedances of existing transformers. Parallel connectivity with other units is achieved by adequately controlling the on-load tap changer.

(7)Customized design:• The Polytransformer can be designed to be

electrically and dimensionally compatible with different transformers existing in a transmission system, meeting particular specifications and applicable standards.

(8)Standardized external components:• To reduce the number of spare parts and to

facilitate the availability of them.


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All in one single product that optimises the required installation dimensions

The polytransformer is:A standard universal multi-voltage spare

autotransformer

That means it has:Compact dimensions to be shipped to

Multiple substationsand

Different voltage ratings to be used to connect different transmission systems.

Different voltage ratings to connect to many transmission systems

A universal multi-voltagecustomized autotransformer

Compact dimensions to be shipped to multiple substations


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PolytransformerCompact: Shipped and installed in many substations.

Multiple voltage ratings.Useful and convenient:

You never know when you may need it.

The Swiss Army KnifeLight and compact: You can carry it on your pocket.


Multifunctional tools


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1 Introduction




5 A practical case

6 Final summary


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The Polytransformer may be used for several applications:

(1) Spare Transformer:The Polytransformer may replace a wide number of different transformers from several substations.The Polytransformer is a multi-voltage spare transformer that can be used as a universal spare unit.

(2) New Substations:The standardized design allow the Polytransformerto be used in new substations. It can be installed permanently on-site or used as temporary replacement of other units.

Advantages and applications of the Polytransformer

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(3) Valuable asset:It can be rented, leased or lent to others in case of emergency or temporary need to cover the requirements of other utilities.

(4) Peaks of load:It could be used to provide additional power in the network during seasonal or emergency consumption peak periods. This reduces the risk of black outs, and will prevent other installed units from being overloaded.

(5) Reduction of inventory and maintenance cost:As the Polytransformer can take the place of different transformers, the total fleet of transformers in a system could be reduced, reducing the inventory, investments and maintenance costs.

Advantages and applications of the Polytransformer

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1 Introduction




5 A practical case

6 Final summary


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The Polytransformer concept was born in collaboration between ‘Red Electrica de España’ (REE) and ABB.REE, as other utilities, has been in a process of standardization of their equipment. They also needed spare transformers to interconnect their 400kV, 230kV and 132kV systems, mainly as a contingency plan in case of emergency and specially in some critical substations.The minimum requirements for the spare unit were to have a three-phase unit with the maximum power rating that could make possible an easy and quick transportation.Additional considerations were taken into account to provide extra features to have, not only a standard spare transformer, but a ... Politrafo

A practical case: REE’s Politrafo

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Shell form.Three phase autotransformer.50Hz.Ynad11 connection.OFAF cooling.On load tap changer regulation at the neutral end (variable flux regulation).

Transformer description and dimensions: Nameplate

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Connection to 400 kV systems on High Voltage Side.Voltage ratios, power ratings and insulation levels:

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Connection to 230 kV systems on High Voltage Side.Voltage ratios, power ratings and insulation levels:

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Transformer description and dimensions: Dimensions

Assembled dimensions and weights:The autotransformer was designed to be mechanically and electrically compatible with other three phase transformers installed in the 400kV transmission system (up to six existing different designs).

1 2 3 4 5 6

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Assembled dimensions and weights:The cooling equipment was designed with oil-air coolers to minimize the total space required for installation.

All the accessories and fittings in this autotransformer are standard, which means that are used in other transformers already installed in the network, mainly to help the maintenance operations and the availability of spare parts.

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Assembled dimensions and weights:

Front View Top View

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Shipping dimensions and weight

Shipping weight:203 Tons

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Paralleling with other transformers

The on load tap changer regulation has 21 positions.

It has a variable flux regulation located at the neutral end.

The regulation range varies depending on the selected connection.

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Paralleling with other transformers

In case that the autotransformer needs to parallel with other units having different regulating ranges those have to be limited in the common part of the ranges.

If the number of regulating positions is different, the transformer could be equipped with a programmable PLC.

This PLC can be programmed to control the load tap changer in the spare transformer and to select the optimum position in every case. It receives indication of the tap position of the transformer to parallel, from that information decides what is the most suitable tap changer position of the controlled spare unit and gives the order to accordingly raise or lower the tap changer position.

OLTC ControlPLC

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1 Introduction




5 A practical case

6 Final summary


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Final summary

The availability of spare transformers in key substations and generating plants is important as a contingency plan in case of a problem or failure.

The Polytransformer is a multi-voltage transformer that provides multiple and additional features in one single product.

It is a compact, customized standard autotransformer with different voltage ratings that could be shipped and installed in many substations.

The polytransformer is a multifunctional product that has different applications. It can help to minimize the number of transformer spares available in a transmission system and to justify the investment in spare units.

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Final summary

The active collaboration between the utilities and the transformer manufacturers is an optimum and proved way to reach mutual objectives like quality and reliability.

In addition, the resultant products are completely adapted to the real needs of the final user.

The Polytransformer is already confirming its competence and performance. Four Polytransformershave been already manufactured and other two are in process. Two of the four existing units are been used to solve urgent transformation needs and have been rented by the owner to other utility, the first one is interconnecting systems from 400 to 230 kV and the second one from 400 to 132 kV.

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The Swiss Army KnifeLight and compact: You can carry it on your pocket.


Compact: Shipped and installed in any substation.Multiple voltage ratings.Useful and convenient:

You never know when you may need it.

Multifunctional toolsFinal summary

Polytransformer

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Final summary

Thank you for your attention!

Documents

The Polytransformer 9CHLIE (*) July 1, 2005 A Multi-voltage Miguel Oliva Transformeraedie.org/9CHLIE-paper-send/PL3.pdf · · 2017-02-06Transformer description and dimensions: Nameplate