CIGRE Reference Paper : Insulation condition during transformer manufacturing

01 August 2018
By Study Committee A2 : C. Bengtsson, C. Krause, A. Mikulecky, M. Scala, M-C Lessard, L. Melzer, P. Hurlet and C. Rajotte


The main objective of this reference paper is to identify gaps in knowledge and issues in relation to verification of cellulosic insulation material properties during and after manufacturing of oil/cellulose insulated power transformers and shunt reactors. It provides input for future work in this field. In addition, it also provides the reader with an overview of this area. Along with the identified gaps, some aspects are discussed in more detail, e.g. physical material parameter(s) that are relevant for a transformer to withstand stresses in service, end-of-life definitions and measurement techniques.

The paper is focused on oil-cellulose insulated, medium- or large power transformers, reactors and similar equipment. It is also confined to cover cellulose properties and their characterization during production of new transformers. The conditions during manufacturing differ significantly from the operation of old transformers in service and the challenges in the characterization of properties differ as well. Hence, the discussion does not cover long term properties of the insulation. It neither includes design dependent issues, nor questions related to short circuit performance.





Transformer insulation

The solid insulation system of power transformers is predominantly made from cellulose and only in rare cases from high temperature resistant polymeric materials. On the conductors, paper insulation is frequently used and in the mechanical structures that are electrically stressed, thick solid cellulose materials, “pressboard”, are used. Cellulose has proven to be a very reliable and cost efficient material for the application as transformer insulation. However, cellulose is hygroscopic, i.e. it easily absorbs moisture when exposed to air, in particular before oil impregnation. The dielectric strength decreases with increasing moisture content and therefore cellulose insulation must be dried before exposed to electric stress. During drying, the transformer is exposed to elevated temperatures which may have a negative influence on the insulation since the aging rate of some material properties increases with temperature [1]. However, the dielectric strength of cellulose deteriorates only to minor extent with thermal aging and is essentially unaffected during the drying process. [2].



Transformer manufacturing


The manufacturing process of power transformers includes mechanical clamping of windings and core and drying- and impregnation of the cellulose insulation. Vapor phase (VP) drying is the most commonly used method, especially for large transformers but a variety of other techniques are also used, for small- and medium size power transformers. All these steps are vital for the long-term function of the transformers. These processes will influence the condition of the cellulose materials (e.g. moisture content), and their functional properties (e.g. paper tensile strength). In general, cellulose insulation materials age with time and temperature under the influence of oxygen and moisture. It is therefore important to ensure that the manufacturing processes are designed in such way that transformers delivered are fit for service and that no unacceptable loss of insulation life has occurred in addition to what can be expected from normal transformer manufacturing. It may be considered that focus is mainly on the mechanical condition and not sufficiently on the remaining water after drying and at the beginning of transformer operation, respectively. As an example taken from ref. [3], it may be preferable to dry down to 0.3 % remaining water content with DP 1050 remaining (lifetime approx. 47 years), rather than DP 1110 with 0.5 % water (lifetime approx. 40 years) or even DP 1160 with 1.0 % water (lifetime approx. 23 years). (These values are based on constant moisture levels in Kraft paper and the example is based on the end-of-life criteria set to DP>200).


Transformer operation and end-of-life criteria


Transformers in operation are subjected to different types of stresses which can be grouped into thermal-, mechanical- and electrical stresses. Examples of these stresses are load or overload (thermal), short circuits (mechanical) and transient over-voltages (electrical). Insulation aging weakens the cellulose fibers, thus mainly affects the transformer’s ability to withstand mechanical stresses occurring during short circuit events and transportation. If the force is high and the insulation paper is brittle (e.g. due to severe aging), the insulation function may be impaired with a resulting internal short circuit inside the winding as a final consequence. This normally leads to failure of the transformer. On a more detailed level, the paper insulation of the winding conductors are subjected to compressive and shear stresses of which the shear stresses are the most dangerous. Aging has little effect on the insulation properties of cellulose [2] and thermal stress itself normally do not cause failures of the transformer but can increases the aging of the cellulose insulation.

End-of-life (EOL) of a piece of equipment, such as a transformer, is in general terms defined as the condition when the equipment no longer can perform its intended duty. The transformer EOL can be separated into technical-, economical- and strategic end-of-life [4]. The most discussed aspect is technical EOL but it is most common to take transformers out of operation for economical- or strategic reasons. Examples of economic reasons are high losses and high maintenance- or insurance costs and smoothing of annual reinvestment budgets. Among strategic reasons are changes in voltage levels or load patterns and obsolescence of some major components, e.g. on-load tap changers. Insulation aging is one aspect influencing the technical EOL by lowering the transformers ability to withstand mainly mechanical stresses. Other important technical factors can be design related (strengths/weaknesses of a particular make), e.g. short circuit strength, dielectric strength and margins, electric resonances in windings, depositions on winding insulation etc. Also historic events like repairs, number of experienced short circuits, transports will influence the technical EOL. It is therefore important to understand that insulation aging alone is not determining the EOL of a transformer [5].

End-of-life of a material such as cellulose insulation is not necessarily the same as end-of-life of the transformer itself and is defined in another way. The function of the material is maintained as long as it withstands various service stresses. EOL of the material is related to the capability to endure these stresses and is normally defined based on a sufficiently high retained strength/value of some important and relevant material property. The properties used in to define technical EOL for cellulose insulation have essentially been tensile strength in the machine direction and the DP value (average viscosimetric degree of polymerization) [6, 7].

It is often convenient to be able to calculate and follow the change of the EOL parameter with time. For tensile strength and DP this is difficult. For tensile strength there is no commonly accepted simple functional form for the time dependence. Also for DP the time dependence function is complex having a fast initial decrease followed by a slower decrease – almost like exponential time dependence. It must be mentioned that the aging conditions such as paper temperature, moisture, and acidity continuously vary with time and are not precisely known, making the mathematical approach even more difficult. An alternative way to characterize the degradation by the number cellulose chain scissions with the advantage of a more linear time dependence (after an initial non-linear increase). In addition the initial DP-value should be indicated.


Cellulosic insulation material properties


General summary

The base material for cellulosic insulation used today is derived from soft wood pulp. The sulfate or the so called kraft wood pulp is most widely used. It is derived from coniferous wood chips which have been chemically and mechanically treated to significantly reduce the amount of non-cellulosic constituents. These removed parts would promote dielectric and chemical instability. The structure within the paper, the fiber length, the bonding between chains and the orientation of these chains form the basis for the mechanical properties of the paper. The aging process in the paper (causing a reduction of the mechanical properties) consists mainly of changes in cellulose chains and bonding between chains [8, 9]. The rate at which the paper is degraded in this aging process is strongly dependent on the structure and the portion of amorphous substance of the paper. Also the presence of nitrogen compounds, added by so called thermal upgrading, will influence the rate of degradation under certain conditions [10, 11]. During VP drying, which can be seen as a thermal conditioning of the paper, a cross linking of the cellulose chains will take place especially for papers made of high grade refined pulp. At the same time, some of the chains will be shortened. The cross linking of the chains will cause an initial increase in tensile strength, especially CMD (cross machine direction) and E-modulus [12].

It is well known that during the initial phase of paper thermal conditioning, such as during drying, there is an increase in bonding between fiber chains causing the mechanical strength to stay constant or even increase [13] while later during the transformer life the degradation of the paper is dominated by the decrease in fiber length, seen as a decrease in DP.


Measurement techniques for unused papers


The specification for new, unused cellulose papers [14] gives definitions and general requirements with agreed parameter values for different properties to qualify different paper types to be used as transformer insulation. However, there are no requirements given for degree of polymerization (DP) for new paper.

The mechanical strength of paper can be measured in different ways such as tensile strength, elongation to break, bursting strength and folding strength [15]. The tensile strength and elongation to break are tested according to [16] and requires a minimum of 9 strips of paper in machine direction (MD) and/or cross machine direction (CMD). Each strip should be straight and perfectly cut with no initiation points for rupture and the strips need to be conditioned before testing. The bursting strength is a biaxial tensile test [17] and will show not only the strength of the paper but also how homogenous the sample tested is. A number of samples, 20 preconditioned pieces, are required. Folding strength [18] tests the brittleness of the paper. Out of the listed tests tensile strength and bursting strength are direct methods which show the strength of the paper, both for new paper and also for used (aged) paper.

The ratio of the average molecular weight to the mass of the monomeric unit represents the average degree of depolymerization (DP) of the paper. This can be determined by testing the specific viscosity of a solution of the paper sample [19, 20] and therefrom the viscosimetric degree of polymerization DPv is calculated. It is thus an indirect method. The sample size needed is very small compared to samples required for mechanical testing. This method will give an average DPv only if the sample is completely dissolved. Cross linked cellulose substance will give a colloidal form of liquid when subjected to copper ethylene diamine solution (CED), which is used during DP-testing. This CED-solution will only be able to partly affect the cross linked parts of the material and the test result will not reflect the true value of degree of polymerization in the sample [15].

A few general remarks – a new paper with very high initial DP could sometimes age at a higher aging rate than a paper with less high initial DP. When comparing different papers, a high DP does not necessarily correspond to high mechanical strength. As already mentioned, the DP number is not a standardized material parameter. It can also be noted that a specification of the level of nitrogen compounds in cellulose is not sufficient to specify the thermal upgrading properties.


Measurement techniques for paper in the transformer manufacturing process


There are no specific requirements agreed on, or specified, for the properties of a paper which has undergone the transformer manufacturing process including drying. To ensure that the paper is dry would be appropriate as well as to ensure that the mechanical strength of the paper is sufficient. The problem is to take samples to be tested that are representing the paper in the transformer windings. Most often the thermal and chemical history during the drying of the winding insulation and paper insulation available for sampling are different. Normally, the paper available for sampling is subjected to a different degradation stress. In addition, the conductor insulation consists of several layers also subjected to different stress – the outer layers normally more stressed during the drying process. For tensile strength or for bursting strength, a large number of samples need to be tested and preferably from a sheet of plain paper and this will not be found on the conductors. Possibly a number of plain sheets of paper could be assembled and put along with the active part through all drying processes for testing after completion of the manufacturing process.

The current industrial practice so far has been to use DP after completed manufacturing although some customers request DP values also before final dryout. Only considering DP will neglect taking the dominating parameter for the insulation EOL into account: the remaining moisture inside the transformer after drying [3, 21]. As cellulose aging is strongly dependent on the moisture content, a higher DP of a delivered transformer may with time be overridden by accelerated aging due to a high moisture content. In addition, DP determination is connected with practical difficulties and problems such as not getting completely dissolved samples giving erroneous results as well as to have truly representative samples [9]. In this respect, the type of drying process, VP drying or Hot Air Vacuum (HAV) combined with impregnation, thermally upgraded paper or standard Kraft paper, all will have different issues in the DP-testing and may have an effect on the results. However, these issues and effects are barely investigated and scarcely reported in literature yet. Although the normalized test methods for DPv [19, 20] are most of the time acceptable [22], there is a lack of definitions and criteria for determining whether the sample has been dissolved completely or not, and there are no numbers given for reproducibility, repeatability or uncertainty. The results are also affected by the experience of the laboratory and its staff. All of this causes uncertainty and could or will lead to discussions among testing laboratories with different test results.


Identified knowledge gaps and issues


The above mentioned methods are associated with advantages and disadvantages in terms of procedure, accuracy and how well they represent the actual stress on the solid insulation in transformers in service. As of today, it is questionable whether a test via an indirect parameter (e.g. DPv) or a mechanical test of a paper sample located somewhere in the VP oven can be suitable for evaluating the aging status of the solid insulation of the transformer. In general, it can be discussed whether any paper mechanical strength test is suitable, – even if taken directly from a conductor. More work needs to address the relevant parameters to be measured that are representative for and have impact on the long term function of a transformer. In addition, practical methods of test which are useful for all types of papers after transformer manufacturing processes, including paper sampling procedure, need to be defined.



Commercial aspects


Any acceptance criteria may have large financial impact both for users and for transformer manufacturers. In particular, as insulation materials in transformers cannot be replaced without rebuilding the active part and replacing the windings, the consequence of a rejection based on excessive paper aging in the factory is huge both in terms of delays to the user and costs to the transformer manufacturer. However, there is no established view on what is reasonable to expect in terms of insulation aging during normal transformer manufacturing and there are no existing guidelines of acceptance criteria nor for compensation if these criteria are not met. Conditions vary considerably from case to case, from very stringent to none at all. This in combination with a very high financial impact makes it an urgent subject to address, preferably within the framework of CIGRE.

Degree of polymerization is the dominating parameter today used for specifying insulation properties after factory drying. As previously discussed in previous sections, loss of insulation life is not linear in DP and loss of insulation life is not necessarily related to the end of life of the transformer itself. As an example calculated from (1) in ref. [3]: if we assume DP=1200 as new paper, and DP 200 as end-of-life, it is often by mistake understood that DP 1000 represents 20 %, or DP 800 represents 40 % lifetime consumed. However, correct values are 3 % resp. 10 % consumed lifetime: DP loss is hence not linear over time. It should also be considered that the relation between the effect of the operating temperature and of the initial DP is such that a change of DP from 1000 to 900 can be compensated by a 0,2 °C reduction of the average lifetime operating temperature of the transformer. This recalculation of time into temperature can be derived using the Montsinger equation for the temperature dependence of the aging rate [6].

It is therefore important that this is considered in the sanctions for exceeding stipulated limits in contracts. It is today common that the consequence of not fulfilling the conditions are not stipulated in the specifications which implies the possibility of rejection based on a small deviation from contractual values. Considering the small impact of a deviation from guarantee values, this is not reasonable, at least not from a manufacturer’s perspective. It is therefore desirable to have guidelines within the industry on reasonable limits where compensation applies, how compensation should be determined and when rejection may be applicable. Similar conventions apply e.g. for losses.



Conclusions and recommendations


This paper gives a general review of the present situation regarding insulation aging during transformer manufacturing. It is of vital interest to ensure that the buyer gets a transformer that is fit for service and that no significant loss of insulation life has occurred in addition to what can be expected from normal transformer manufacturing. It is of equal importance that there are commonly accepted guidelines within the industry how to specify, guarantee, verify and to compensate or correct potential deviations from specified properties.

The paper points at existing uncertainties in the areas of measurement techniques, insulation material properties and commercial aspects as well as on the relevance of the commonly used measurements of degree of polymerization (DP). Based on these observation, it is recommended that the international community addresses these issues in order to fill the discussed gaps.

In summary, the main gaps to fill are the following:

  • What is (are) the recommended technique(s) to determine the status of the paper after the transformer drying?
  • If physical cellulosic insulation samples are required: how to get representative samples before and after the drying process?
  • What are the guidelines for acceptance criteria to evaluate the aging caused by the drying process?
  • What are the guidelines for measures and compensation in case the criteria are not met?




[1] A. Mikulecky et al., “Research on Insulation Aging on Transformer Models”, IEEE SDEMPED, Grado Italy, September, 2001.

[2] H.P. Moser, V. Dahinden, "Thermal aging of oil/Transformerboard insulation systems" in Transformerboard II, second edition, Printing Styrian, Graz, pp. 149-156, 1999.

[3] C. Krause, “Thorough Drying of UHV Transformer Insulation for Minimum Moisture Versus Premature Aging by Drying – A Technical Conflict”, CIGRE Colloquium Shanghai, paper FP0588, 2015.

[4] L. Pettersson, “Estimation of the remaining life of power transformers and their insulation”, Electra, No 133, 1990.

[5] L. Pettersson, N.L. Fontana, U. Sundermann, “Life Assessment: Ranking of Power Transformers Using Condition Based Evaluation. A New Approach”, Cigré 1998, paper 12-204.

[6] IEC 60076-7:2005, “Loading guide for oil-immersed power transformers”.

[7] IEEE C57.91:2011, “IEEE Guide for loading mineral-oil-immersed transformers”.

[8] "Aging of cellulose in mineral-oil insulated transformers", CIGRE Brochure no. 323, TF D1.01.10, 2007.

[9] “Aging of liquid impregnated cellulose for power transformers”, CIGRE Brochure, WG D1.53, to be published.

[10] T. Prevost, "Thermally upgraded insulation in transformers", EIC conference, Indianapolis, 2005.

[11] O. Arroyo-Fernández, I. Fofana, J. Jalbert et al., "Assessing Changes in Thermally Upgraded Papers with Different Nitrogen Contents under Accelerated Aging, IEEE Transactions on Dielectrics and Electrical Insulation Vol. 24, No. 3; pp1829-1839, 2017.

[12] E.L. Back, “Thermal auto-crosslinking in cellulose material”, Pulp and Paper Magazine of Canada, 1967.

[13] J.M.B. Fernandes Diniz et al., “Hornification – its Origin and Interpretation in Wood Pulps”, Wood Sci Technol 37, pp 489, 2004.

[14] IEC 60554-2, “Cellulosic papers for electrical purposes - Part 2: Methods of test”

[15] W.G. Lawson et al., “Thermal Aging of Cellulose Paper Insulation”, IEEE Trans. El. Ins., Vol EI-12, No. 1, 1977.

[16] ISO 1924-2, “Paper and board -- Determination of tensile properties”

[17] ISO 2758, “Paper -- Determination of bursting strength”

[18] ISO 5626, “Paper -- Determination of folding endurance”

[19] IEC 60450, “Measurement of the average viscometric degree of polymerization of new and aged cellulosic electrically insulating materials”

[20] ASTM D 4243-99. “Standard Test Method for Measurement of Average Viscometric Degree of Polymerization of New and Aged Electrical Papers and Boards”

 [21] L. Lundgaard et al., Aging of Oil Impregnated Paper in Power Transformers, IEEE Transactions on Power Delivery, Volume: 19, Issue: 1, Jan. 2004

[22] CIGRE Technical Brochure 494, WG D1.03:2012, “Furanic compounds for diagnosis”


Download this Reference Paper : Reference RP_299_1


CIGRE Reference Paper : Power system restoration – World practices & future trends

01 June 2019
By S. Almeida de Graaff (NL) – SC C2 Chair



Complete or partial blackout of the electric power grid does occur from time to time, despite prudent planning and operations, due to disturbances that either exceed the basic design criteria, or due to various causes such as natural disasters, multiple equipment failure, protection relay miscoordination or malfunctioning, and human errors. Restoration of the power system, following such disturbances, is an extremely important aspect of the System Operator’s role in managing the bulk power system and has as objectives to enable the power system to return to normal conditions securely and rapidly, minimizing restoration time and associated losses, and diminishing adverse impacts on society.


State of the art


In general, there are two basic strategies for power system restoration, namely the bottom-up and the topdown strategy.

The bottom-up restoration strategy is based on the use of blackstart generators (those able to re-energise the system without relying on the external electric power transmission network), and applies in case of total system blackout and non-existent interconnection assistance. On the contrary, the top-down restoration strategy is based on neighbouring interconnections. These are used to energize the bulk power transmission system first, after which loads and other generators are energized. Both approaches have their advantages and disadvantages, and many system operators choose a hybrid approach to restoration (see Table 1 - Examples of implemented blackstart strategies).



Restoration in the future


A common practice for System Operators is to use conventional power plants for system restoration, making it a stable and predictable process. In a future where less or no synchronous generators will be available, it is important to rethink restoration strategies. Due to the fact that the share of renewable energy sources (RES) in distribution networks is nowadays significant (with the tendency to grow even further), there is a need for TSO/DSO integrated restoration plans, which will involve increased coordination, information exchange, joint operator training, and most likely common tools. Depending on the amount as well as controllability of DSO-connected RES, the responsibilities and contribution of each entity in the restoration process will differ.

With the increasing RES and other power electronics devices in the power system, their capabilities need to be utilised as much as possible. Whereas HVDC links are not commonly used for providing restoration service, their participation is expected to increase in the future. The functionalities of these links can be utilised in order to aid the system restoration, including providing active and reactive support during blackstart and building of the cranking path. Furthermore, Battery Energy Storage Systems (BESS) can be used in several ways for supporting the restoration process. One example is the participation of BESS in load restoration. Another example is the use of BESS as blackstart source for providing the required power to non-blackstart generators.

The role of Wide Area Monitoring Systems based on Phasor Measurement Units (PMUs) for restoration purposes is expected to increase in the future. When compared to traditional SCADA measurements, synchrophasors have an added value of synchronised voltage phase angle information between areas that have to be re-energized and/or re-connected, which can significantly benefit the restoration process. In the preparation phase of the restoration process, and when complemented with state estimation data, the synchrophasors provide precise information of the remaining system, its division in islands and available components in the system. This information helps to construct the restoration strategy. From a restoration viewpoint, the restoration stage can be enhanced with critical data such as synchrophasor measurements from generating units and critical load.


Concluding remarks


System Operators have predominantly been using conventional synchronous generators in the restoration process. With the rapidly developing power system, changes in the power system restoration strategy become necessary to adequately address the future challenges.

With increasing distributed energy resources, the role of the distribution system operator in power system restoration will become more important, where coordination between different stakeholders will be key. Furthermore, this increasing generation in distribution networks demands an improved observability and increased information exchange. The use of WAMS can greatly help to achieve this, especially during restoration activities where situational awareness in the control room is of utmost important. With increasing integration of power electronics interfaced devices in the power system, it is also worth investigating how these can support the system operator in enabling an effective and efficient restoration process. The use of available HVDC links and battery energy storage systems in the restoration process is expected to increase in the future. This is tackled in the newly established working group C2.26 “Power system restoration accounting for a rapidly changing power system and generation mix”.


Further reading


This article is a summary of a Reference Paper prepared by a small task force of Study Committee C2 – System Operation and Control. The full paper elaborates in more detail also on the currently used restoration strategies throughout the world, the importance of operator training for restoration and addresses the future, providing examples of innovative solutions. Readers are encouraged to reach out and read the full paper in the CIGRE Science & Engineering Journal’s Volume No 14, June 2019 issue.


Download this Reference Paper : Reference RP_304_1


CIGRE Reference Paper : Sustainability – At the Heart of CIGRE's WorkSustainability – At the Heart of CIGRE's Work

12 September 2018
By Konstantin Staschus, Mercedes Vazquez and Henk Sanders


Sustainability is a key driver of many developments world-wide, and quite notably for power systems, thanks to the December 2015 Paris Agreement on climate protection with its actionable worldwide consensus and the Sustainable Development Goals (SDGs) adopted by the United Nations in September 2015. CIGRE, as the ‘global expert community for electric power systems’, is engaged in supporting the SDGs, the Paris Agreement, and sustainability in general, and pursues sustainable electricity for all.


This Reference Paper describes how CIGRE contributes to global sustainability and the SDGs, partly by adhering to sustainable organizational practices itself, but even more importantly by supporting many SDGs through its global work related to energy, emissions, and climate change. This paper thus lays the foundation to focus CIGRE's work more systematically on sustainability; and for the Technical Council to include further aspects of sustainability in the next strategic plan on which CIGRE's work should focus.


The paper thus means to clarify both for CIGRE Members, its Councils and Study Committees, and for external parties - governments, regulators, industry, academia -how CIGRE already supports the sustainability goals, and how we will take sustainability into account when defining our future work.


For the same reasons outlined above, most worldwide organizations related to energy are clarifying and emphasizing their contributions to sustainability; as one example we cite here the International Energy Agency (IEA), whose Executive Director Fatih Birol has published “Energy is at the heart of the sustainable development agenda to 2030” in March 2018, with the IEA website since tracking the energy contributions to the SDGs.


The 17 SDGs designated by the United Nations are:

Just looking at these titles it becomes clear that power systems – and thus the expertise CIGRE contributes worldwide to well developed and managed power systems – are of direct relevance to several of these. In analysing our contributions to the SDGs, CIGRE’s Technical Council identified nine SDGs for which CIGRE’s contributions are especially relevant, and these can be grouped into the four dimensions of climate protection, efficiency, global cooperation, and development. Sections 2 through 5 of this reference paper describe CIGRE’s contributions through global power system expertise to the nine SDGs, structured along the four dimensions. Section 6 describes how CIGRE’s current and evolving organizational practices support the SDGs (including a check and adjustment of CIGRE bylaws to further improve our sustainable practices). Section 7 provides conclusions, including a summary how certain CIGRE activities might be prioritized over the coming years towards even stronger sustainable impact. The remainder of this introduction describes in general terms how CIGRE, as an association of experts, universities, electrical equipment manufacturers, and electric utilities, contributes to a world evolving towards better sustainability.


With over 14,000 members across 90 countries, CIGRE aims to develop and implement tangible benefits in electric power systems for all its stakeholder and society in general. As CIGRE’s Strategic Plan states, “Electricity is vital for the development and well-being for all people of the world. As the Earth’s population continues to increase, so too does pressure on the planet’s key resources, especially food, clean water and energy. Global development and peace will in part be dependent on equitable access to these key resources. The demand for energy in the world will continue to grow while at the same time traditional carbon-based energy resources are under increasing scrutiny due to environmental considerations. As well as maintaining existing infrastructure, development of sustainable energy resources, often widely dispersed, will be essential to meet this growing demand. We must also endeavor through our collaborative efforts to further the global community of electricity for all in the world who do not benefit from electricity today.


In this context of increasing electricity’s global relevance for the society and sustainability, CIGRE’s purpose is to foster engagement and knowledge sharing, enhancing expertise among power system professionals globally to enable the sustainable provision of electricity for all. The outcome of the collaboration of – at any given time – over 3,500 active experts within 240 active working groups that produce approximately 45 technical brochures a year is the creation and distribution of unbiased and authoritative technical reference resources that contribute to the betterment of the industry and the expertise of the people working within it. In particular, we synthesize state-of-the-art and worldwide best practices; develop guidelines and information to aid the development of new technologies and techniques. By applying the knowledge generated in the CIGRE reference resources, manufacturers build better electrical equipment that contributes to more sustainable energy systems, academics educate engineers with better understanding how to improve electric systems and sustainability throughout their careers, and utilities develop and operate their systems more economically, more reliably and more sustainably.



CIGRE and climate protection


IN SDG 13, Climate Action is the key issue of this dimension: "Take urgent action to combat climate change and its impacts".

It is about strengthening resilience and adaptability from hazards and natural disasters that are climate related.

It is about developing and promoting mechanisms to increase the capacity of effective climate change-related planning and management.


What does SDG 13 mean for CIGRE?


The electric industry and climate mutually influence each other. The industry faces outages due to hazards or natural disasters, a more volatile balance, a variable supply and demand, yet we are developing electric vehicles that will help protect the climate through their efficiency. Climate change and its necessary actions have many effects on our industry; from a changing market to integrating renewable energy sources (RES), or from innovation in storage to off-grid solutions, every aspect of CIGRE’s work will be influenced by this changing world.


Our industry is contributing more and more to climate change protection. The Paris Agreement and the worldwide targets of reducing CO2 emissions have enormous influence on our industry: integrating RES into the grid, looking for off-grid solutions, increased emphasis on storage: it all provides improvement for climate protection.


The CIGRE work contributes to the following SDG 13 actions:

  • Strengthen resilience and adaptive capacity to climate-related hazards and natural disasters in all countries;
  • Integrate climate change measures into national policies, strategies and planning;
  • Improve education, awareness-raising, and human and institutional capacity on climate change mitigation, adaptation, impact reduction and early warning.


A side effect of these actions will be attention to:


SDG 14 and SDG 15 - Mostly this concerns actions about environmental issues, obligatory by law, but sometimes on a more voluntary basis, to achieve more stakeholder engagement.


SDG 14: "life below water": CIGRE addresses in several Study Committees and Working Groups (WGs) offshore developments for the power sector. Offshore wind has proven its worth in many parts of the world and underwater turbines are also a fast developing sector. All our colleagues working offshore have to deal with the environmental protection of sea life when installing sea cables and offshore platforms. In many situations, laws are in place requiring that care is given to sea life but the engagement to protect life below water benefits all stakeholders.


SDG 15: "life on land": A lot of the work of CIGRE Study Committees and WGs relates to infrastructure on land. Like SDG 14, this mainly concerns the environmental issues related to our work such as noise and visual pollution. Around the world, our industry takes care to protect our biodiversity through bird and animal protection, landscape and corridor management, reducing the use of greenhouse gases like SF6 and so on. As with SDG 14, there are often legal requirements but more often companies undertake actions to support the SDG and/or to gain more public trust.



CIGRE and efficiency


SDG 7 is at the heart of what CIGRE does.


It is about providing universal access to affordable, reliable, and modern energy services.

It is about increasing the share of RES in the global energy mix.

It is about expanding infrastructure and developing technology to be able to supply modern sustainable energy services to all countries and all people around the world.

It is about increased cooperation that facilitates access to research and technology of clean energy, including renewables.


What does SDG 7 mean for CIGRE?


SDG 7, "affordable and clean energy", addresses one of the most basic needs of society: access to affordable, reliable, sustainable, and new energy sources. Without any doubt, this is a goal where CIGRE plays a major role. CIGRE is the world’s most recognised international non-profit association for promoting expert collaboration through knowledge sharing to improve the electric power systems of today and tomorrow. CIGRE has long embraced the challenges of integrating sustainable and new energy sources without compromising the reliability of supply.


CIGRE is acting in a fast-changing sector. While in the past we only transported electricity from a fixed number of land-based fossil-fuel plants, now we are faced with multiple onshore and offshore energy sources, and a complex, cross-border energy market. Some consumers are now producers as well, feeding energy from their solar panels or e-cars back into the system. In this exceptionally fast-evolving market it can be hard to plan for the long term. We need to make sure we keep the lights on at all times, while facilitating the integration of present and new market players. Above all, we must ensure that our investments are not providing society with expensive assets that could soon become obsolete.


The CIGRE work contributes to the following SDG 7 actions:

  • By 2030, increase substantially the share of RES into the global energy mix
  • By 2030, ensure universal access to affordable, reliable, and modern energy services
  • By 2030, double the global rate of improvement in energy efficiency
  • By 2030, enhance international cooperation to facilitate access to clean energy research and technology, including renewable energy, energy efficiency and cleaner, and more innovative fossil-fuel technology, and promote investment in energy infrastructure and clean energy technology
  • By 2030, expand infrastructure and upgraded technology for supplying modern and sustainable energy services for developing countries, in particular lesser-developed countries, small island developing states, and land-locked developing countries, in accordance with their respective programmes of support.


By supporting these actions, CIGRE work will also have a major influence on:


SDG 9, "industry, innovation and infrastructure": CIGRE facilitates sustainable and resilient infrastructure development in developing countries through enhanced financial, technological and technical support to African, Latin American, and certain Asian countries, and other lesser developed countries. Advanced systems that have been tested in mainstream networks can be deployed in areas where none even exist now.


SDG 11, "sustainable cities and communities": One of the major impacts foreseen will be the power requirement for electric vehicles. The necessary strengthening and reinforcement of long-line transmission and distribution systems to import necessary power to cities, as well as the developing structure of microgrids, will reinforce the sustainable nature of cities. The knowledge CIGRE experts share contributes to reducing the adverse per capita environmental impact of cities, including by paying special attention to air quality and municipal and other waste management.


SDG 12, "responsible consumption and production": CIGRE work can encourage companies, especially large and transnational ones, to adopt sustainable practices and to integrate sustainability information into their reporting cycle, and it can assist developing countries to strengthen their scientific and technological capacity to move towards more sustainable patterns of consumption and production. The integration of storage systems, on-demand power generation, and more advanced network management can reduce the worldwide reliance on older generation options.



CIGRE and global cooperation


Global cooperation is the backbone of CIGRE’s principles and leads us clearly to:       


It is about strengthening international cooperation on science, technology, and innovation, and easing access to this information.

It is about sharing knowledge and facilitating technologies.


What does SDG 17 mean for CIGRE?


SDG 17; "partnerships for the goals" is in the heart and in the genes of CIGRE. A successful sustainable development agenda requires partnerships between governments, the private sector, and civil society. These inclusive partnerships, built upon principles and values, a shared vision and shared goals, that place people and the planet at the centre, are needed at the global, regional, national and local level. The inherent ideologies of CIGRE lend our global base of expertise to lead all levels of decision makers.


SDG 17; "partnerships for the goals” is CIGRE’s call to act. Urgent action is needed to mobilize, redirect, and unlock the transformative power of trillions of dollars of private funding to deliver global sustainable development objectives. Long-term investments are needed in critical sectors, such as developing countries, but also in under maintained ageing networks that can no longer keep up with technological advances. These include sustainable energy, infrastructure and transport, as well as information and communications technologies. Review and monitoring frameworks, regulations and incentive structures that enable such investments must be retooled to attract investments and reinforce sustainable development. Supreme audit institutions and oversight functions by legislatures must be strengthened.


That CIGRE lives and promotes global cooperation does not need much explanation, as CIGRE is a worldwide organization, with connections to all types of companies in the electricity sector: utilities, generation companies, manufacturers, governments, science, consultancies, civil society, and CIGRE collaborates with several similar global institutions including IEEE and the World Bank.


CIGRE and development


There are several SDGs partly related to economic and societal development:


What do these mean for CIGRE?


SDG 4: “quality education is one of the main conditions to fulfil all the UN’s sustainability goals. Obtaining a quality education is the foundation for improving people's lives. It is not in the scope for CIGRE to organize worldwide access to affordable and qualitative technical, professional education. It is also not a task for CIGRE to make sure that by 2030, all young men and women around the world are literate. However, even if education is not CIGRE's primary business, the way CIGRE acts and is organized, contributes strongly to better education in the world: CIGRE is about sharing knowledge and working together with colleagues from all over the world.


Electrification is crucial for community development and for personal empowerment. These ideologies are essential for an improved quality of education. CIGRE is working on a number of educational improvements: more women in the power industry, encouraging young people to become CIGRE members. Universal access to electricity is also high on the list of CIGRE priorities, e.g. the Africa dissemination and lesser-developed countries, in cooperation with the World Bank.


In this context, CIGRE also contributes to SDGs 5 and 9:

SDG 5, "Gender equality": CIGRE facilitates and encourages women in CIGRE and thus also in their role in their companies and countries.

SDG 9, "industry, innovation and infrastructure": CIGRE facilitates sustainable and resilient infrastructure development in evolving countries through technological support to African countries and other less industrialised countries.



CIGRE bylaws and practices for our own organisational sustainability


CIGRE’s own practices already address sustainability related to the following SDGs:


SDG 5; "gender equality", through the project “Women in CIGRE”.


SDG 16; "peace, justice and strong institutions", by CIGRE’s own “Antitrust Guidelines for Meetings” which exclude any corruption or bribery from CIGRE work. In general, CIGRE developed itself as an effective, accountable, and transparent institution, and ensures responsive, inclusive, participatory, and representative decision-making at all levels.


As further attention to these and other SDG's is needed, section 7 specifies how CIGRE's practices as well as CIGRE's overall contributions to sustainability through its work products can be further improved.


Summary and recommendations


This Reference Paper has shown that CIGRE contributes to 9 out of the 17 United Nation’s Sustainable Development Goals. Through the efforts of 3,500 experts in 240 working groups, producing an average of 45 new power industry reference documents per year, CIGRE helps thousands of readers in 90 countries to improve and operate their electricity systems better, which often means in a more sustainable way. The nine primary SDGs affected by CIGRE’s work are:


  • First and foremost, SDG 13, "take urgent action to combat climate change and its impacts”: many of the CIGRE WGs study how electric system equipment, subsystems, and the entire system can be developed, improved, and operated reliably with ever increasing RES. Renewable energy is one of the most important ways to combat climate change.
  • Equally important, SDG 7, “clean and affordable energy”, is supported by numerous CIGRE WGs, by describing how equipment, subsystems, and the overall electric system work efficiently, how environmental impacts are reduced, and how RES make the overall system cleaner.
  • And at the heart of all CIGRE’s work as a global cooperative association is SDG 17, “partnerships for the goals”.
  • Also supported through CIGRE’s effort are innovations in SDG 9, "industry, innovation and infrastructure", SDG 11, "sustainable cities and communities" and SDG 12, "responsible consumption and production" (all related to the power system efficiency effects of CIGRE’s work), SDG 14, “life below water” and SDG 15, “life on land” (related to the environmental effects by some CIGRE WGs), and SDG 4, “quality education”, SDG 5, “gender equality”, and SDG 9, "industry, innovation and infrastructure" (related to CIGRE’s contributions to an innovative, non-discriminative, and productive power industry work environment).


Constant contributions to global energy systems are made through CIGRE’s reference documents and to CIGRE’s own organizational practices however further improvements for sustainability are possible and should be pursued systematically.


The following activities in CIGRE should be strengthened, to turn what are now very general parts of the SDGs into more electric system-relevant parts:


  • SDG 5, “gender equality": ensure women's full and effective participation and equal opportunities for leadership at all decision making levels within CIGRE.
  • SDG 7, “affordable and clean energy": increase the focus of CIGRE WGs on ensuring universal access to affordable, reliable, and modern energy services; on energy efficiency; on facilitating access to clean energy research and technology, including renewable energy, energy efficiency, and advanced and cleaner fossil-fuel technology (also with more focus on pollutants and particulates from generation and networks); on investment cases for energy infrastructure and clean energy technology; and on expanding infrastructure and upgrading technology for supplying modern and sustainable energy services for all in developing countries.
  • SDG 9: "industry, innovation and infrastructure": enhance technological and technical support to lesser-developed countries.
  • SDG 11: "sustainable cities and communities": increase attention (in certain WGs) on sustainable and resilient buildings utilizing local raw materials; to protecting and safeguarding the world's cultural and natural heritage; and to reducing the adverse per capita environmental impact of cities, including by paying special attention to air quality, and municipal and other waste management.
  • SDG 12: "responsible consumption and production": promote public procurement practices that are sustainable, in accordance with national policies and priorities, and encourage companies, especially large and transnational companies, to adopt sustainable practices and to integrate sustainability information into their reporting cycle. Improve CIGRE’s publication practices to contribute to people everywhere having the relevant information and awareness for sustainable development and lifestyles in harmony with nature, and to support developing countries to strengthen their scientific and technological development to move towards more sustainable patterns of consumption and production. Some CIGRE WGs may also be able to address inefficient fossil-fuel subsidies that encourage wasteful consumption.
  • SDG 13: "climate action": More CIGRE WGs will need to address resilience and adaptive capacity to climate-related hazards and natural disasters on all continents, and the integration of climate change measures into national policies, strategies, and planning. CIGRE’s work should systematically bear in mind the need to improve education, human awareness, and institutional capacity on climate change mitigation, adaptation, impact reduction, and early warning signs.
  • SDG 14: "life below water": especially for connecting offshore windfarms, wave and subsea turbines, CIGRE needs to launch more WG's about the effects of these connections on life below water.
  • SDG 15: "life on land": although this topic is well covered in WG’s, CIGRE needs to ensure that this topic remains a priority.
  • SDG 17: "partnerships for the goals": By design, most of CIGRE’s work promotes the development, transfer, dissemination, and diffusion of environmentally sound technologies to developed and developing countries, and this should be made more explicit in CIGRE’s global communications efforts. Multi-stakeholder partnerships that mobilize and share knowledge, expertise, technology, and financial resources can also be used to support the achievements of the sustainable development goals in all countries while encouraging and promoting effective public, public-private, and civil society partnerships, building on the experience and resourcing strategies of partnerships.


In the coming months, the CIGRE TC will decide how to drive these recommendations into action, and how to monitor and ensure their progress.


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