Intelligent system solutions for distribution networks · PDF filefundamental problems in the electricity sector resulting from fixed ... OLTC-regulator (Regulating algorithm/Control/Diagnosis)

Intelligent system solutions for distribution networks

Power Distribution Smart Grid Solutions

The future of electricity networks – smart grids

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What is a smart grid?A smart grid is an electricity network which intelligently coordinates the actions of all connected users – producers, consumers, storage units – in order to ensure efficiency in an environmentally sustainable, economically viable and reliable electricity supply.

Decentralized energy supply spreading quickly

In parallel with the process of liberalization, the last few years have also witnessed a huge increase in decentralized energy sup-plies. This includes both off-grid and on-grid operation of small supply units. The generation units can be operated at the site of use and are then either used to directly cover requirements or the electricity produced there is made available to the supply system.

This development has been accelerated by legislation to give prio-rity to renewable energies (Renewable Energy Law). This law came into force in 2000 and stipulates that grid operators must link to, accept and pay plants to generate electricity from renewable sour-ces. Since most such electricity comes from decentralized units, there has been a partially subsidized increase in this area. This

situation has brought with it new requirements for the absorbing electricity network as the load flow direction may now reverse and do so with huge fluctuations. If electrical energy is distributed in the usual way "from top to bottom", there are now more and more generators feeding into the grid starting at the medium voltage level.

380 kV 220 kV

110 kV

30 kV 20 kV 10 kV

600 V 400 V240 V

Future grid operation (controlled online): Fluctuating, decentralized power supply in various directions

Standard grid operation (from top to bottom): Load-dependent, centralized power supply in one direction

Conventional power stations

Supplier

Private electricity generator

Generator of renewable power

Development and trends - from the standpoint of a smart grid operator

Change on the energy markets –change in infrastructure

The energy markets are undergoing fundamental change. At the end of the 21st century, we will have renewable energy systems where load is dictated by generation, renewable sources of energy are the main player and energy effi ciency measures start to be-come effective.

Three trends are already becoming apparent today:

| Liberalization of the energy markets is resulting in the unbundling of what were once vertically integrated structures of generation.| Huge growth in decentralized energy generation, especially renewable energy| Need for effi cient use of energy to reduce greenhouse gas emissions

Coupled with the world's ever-growing appetite for energy, this is placing much greater requirements on the grid and its equipment - affecting distribution networks in the future too.

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Industry

Private households

Electric cars andenergy storage facilities

Consumer + storage facility

Regulation of the fl ow of electricity in grid control centers

Smart grids link up and control fl ows of data and electricity


120 GW

100 GW

80 GW

60 GW

40 GW

20 GW

0 GW2008 2009 2010 2011 2012 2013

AsiaNorth America Europe

Latin AmericaPacificMiddle East / Africa

Expected Growth of Wind Energy

Source: DCTI Solar Energy Study

Expected Growth of Photovoltaic Installations

35,072

2,286 3,564 4,9747,695

19,285

13,948

26,483

45,610

58,032

30,000 MWp

25,000 MWp

20,000 MWp

15,000 MWp

10,000 MWp

5,000 MWp

0 MWp

70,000 MWp

60,000 MWp

50,000 MWp

40,000 MWp

30,000 MWp

20,000 MWp

10,000 MWp

0 MWp

Newly installed

Cumulative

2004 2005 2006 2007 2008 2009 2010 2011 2012 2013926 1,278 1,410 2,721 6,254 5,336 7,198 8,589 10,538 12,442

Source: DCTI Solar Energy Study

Newly installed capacity cumulative capacity

Increasing demand for energy – changes to the grid structure

Intelligent regulation in distribution networks

Intelligent grid regulation will be needed in the distribution net-works of the future to balance production and consumption, to maintain a secure supply and to comply with voltage bands (to prevent electrical equipment from being destroyed); communi-cative links are important for this reason if no other. Advances in information and telecommunications technology are evolving rapidly. The Internet and wireless transmission technologies such as GSM and the associated applications have now become the norm. There is one obvious way in which this potential can be used to address the complex requirements existing in the generation, distribution and supply of energy.

Information and communication technologies (ICT) may have an important role to play in reducing energy consumption and op-timizing the energy system because they can be used to address fundamental problems in the electricity sector resulting from fixed bonding to the grid and the fact that electricity cannot be stored: In order to avoid bottlenecks and system overloads, supply must be able to respond at all times to the demand resulting from the decentralized decisions made by households and businesses. It is important to remember that both too great and too low a demand can trigger an instable system status.

No exchange or a slow exchange of information and/or links be-tween information result in production and consumption not being sufficiently matched. In the future, new products and systems must therefore take account of the needs of both communica-tion and load flows. Huge growth in the number of decentralized suppliers, such as roof-mounted photovoltaic systems, mini com-bined heat and power plants (CHP) or small wind farms results in greater voltage fluctuations in the distribution network and may even violate the permitted voltage band. Harmonic currents from electronic consumers and voltage imbalances are other aspects which will increasingly have to be taken into account.

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One solution: The controllable local grid transformer

The problem of voltage fluctuations and band violations can be solved using a controllable local grid transformer for example. Maschinenfabrik Reinhausen (MR), with its expertise as a global market leader in voltage regulation, focused on solving this issue at an early stage and realized that any approach needed to offer the operator the following benefits:

| Compliance with the permissible voltage limits| Optimized use of existing reserves| Grid extension measures can be deferred or avoided altogether.| Greater potential for the integration of decentralized supplies is made possible.

MR Smart Transformer – the systematic response

The MR Smart Transformer features transformation, actuator, regulator, sensor, communication, data management and intel-ligence system components. This level of the MR iPOWER system is intended as a minimal unit for use in local grid stations. With the addition of a medium- and low-voltage connection, this is the independent, regulated equivalent of today's uncontrolled local grid station.

Actuators: Two technical solutions available

A controlled transformer is the centerpiece of the station. To date MR has equally pursued two technical solutions at various stages of development:

| Classic principle of actuators based on proven oil switch technology in use for decades

On the basis of proven tap-changer technology at the high and maximum voltage level, Maschinenfabrik Reinhausen has managed to now make this technology suitable for use in local grids. By slightly increasing its length and height, the trans-former now covers applications up to the 630 kVA connection class.

| Hybrid principle as a combination of semi-conductor switching element and mechanical main switching contacts

Innovative combination of semi-conductor switching elements and mechanical contacts means that less space is needed in the transformer. Simply swapping the transformation and actuator unit makes this a great update solution for existing stations.

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Actuator

Transformation

Regulator

Sensors

Communication

Data management

Intelligence

Actuator

Transformation

Regulator

Sensors

Communication

Data management

Intelligence

SMART TRANSFORMER

Special actuator regulation (voltage regulation) is needed for tap changes. This comprises:

| Regulation unit for monitoring voltage and controlling the functions of the conventional actuator| Regulation unit for monitoring voltage and controlling the functions of the hybrid actuator

Depending on the application, additional sensors are needed to monitor the station functions and/or to implement a self-suffi-cient station.


Classical actuator principle Hybrid actuator concept

400 V-local grid Oil

local grid transformer

20 kV medium-voltage power grid 20…24 kV

3~

PV

–3~

PV

–

400 V- local grid


3~

PV

–3~

PV

–

MMI OLTCInterface sensor

OLTC-regulator(Regulating algorithm/Control/Diagnosis)



voltage recording

V

controlling & status

local grid station local grid station

Control technology Control technology

controlroom

controlroom

Classical actuator principle Hybrid actuator concept

400 V-local grid Oil

local grid transformer


3~

PV

–3~

PV

–

400 V- local grid


3~

PV

–3~

PV

–





voltage recording

V

controlling & status

local grid station local grid station

Control technology Control technology

controlroom

controlroom

The complete solution: the MR iPOWER system

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Actuator

Transformation

Regulator

Sensors

Communication

Data management

Intelligence

SMART TRANSFORMER Low voltage

connectionStorage

Compen- sation

Medium voltage

connection

Generator

MR iPOWER system In addition to the system components of the MR Smart Trans-former, the MR iPower system also comprises the following components:

| Low-voltage connection| Medium-voltage connection| Energy storage system (e.g. battery storage)| Compensation system (MR Power Quality Management)| Self-sufficient generation unit (e.g. renewable energy generators)

In both variants, the system functions as the generation unit which either acts totally self-sufficiently as the generator (e.g. use when fully off grid or use in areas with poor infrastructures, including use in emergency areas for disaster operations) or only with one grid connection for covering peaks in consumption which cannot be provided by the unit itself. Use and specification of the compensation and/or storage unit depends on the generation unit used and/or the external application.

Based on current technical standards, the followingsystem components are available as options:

| Micro photovoltaic systems (PV)| Micro wind turbines (WT) | Systems for the generation of biogas, which is implemented in the combined heat and power (CHP) module. | Systems using geothermal energy| Heat pumps

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MR iPOWER project in Oberursel

Working jointly with Süwag Energie (Frankfurt), the first complete MR iPOWER system was commissioned as a 20 kV pilot plant at Oberursel on a site belonging to MR's subsidiary Messko GmbH.

This comprises:

| MR iPOWER system| Wind energy system of 6 kWp (grid)| Photovoltaic system of 20 kWp (grid)| Combined heat and power (installed 08/2011)| Battery storage system (installed 08/2011)| Electric car charging station

The iPOWER system will on the one hand supply Messko GmbH with energy and on the other hand feed excess energy produced to the Süwag grid.

Here are some of the physical parameters to be monitored by way of example:

| Oil temperature of transformer| Winding temperature of transformer| Oil quality level of transformer| Oil flow within transformer and attached cooling system| Current sensors| Voltage sensors

DGA monitoring (gas-in-oil monitoring) can be fitted as an option and in large units. The analyzer is used to extract and measure gases dissolved in the transformer's insulation liquid. Based on the trends indicated, a statement can be made on the transformer's errors, maintenance cycles and service life. The individual pieces of physical information are merged in a central data manager.

Your contact for all issues relating to Power Distribution and MR iPOWER system:Maschinenfabrik Reinhausen GMBH Ansgar Hinz, Head of Power Distribution

Postal address:Messko-Platz 1, 61440 Oberursel, Germany Phone: +49 6171 6398-0 Fax: +49 6171 6398-98 Email: [email protected]


Please note: The data in our publications may differ from the data of the devices delivered. We reserve the right to make changes without notice. AF2608806/00 EN – 08/11 – F0293600 – uw – ©Maschinenfabrik Reinhausen GmbH 2011

Maschinenfabrik Reinhausen GmbH Phone: +49 941 4090 0 www.reinhausen.comFalkensteinstrasse 8 Fax: +49 941 4090 700193059 Regensburg, Germany E-mail: [email protected]


Documents

Intelligent system solutions for distribution networks · PDF filefundamental problems in the electricity sector resulting from fixed ... OLTC-regulator (Regulating algorithm/Control/Diagnosis)