CIGRE Session 46 (August, 21-26, 2016)
The main discussion themes:
- Eco design of equipment
- Maintenance, refurbishment and life time of equipment
- Real time monitoring of equipment and systems
- Development of DC solutions
- Coordination between TSOs – Transmission and System Operators
- Public acceptance of equipment
- Integration of renewable power sources
- Active distribution systems
- Information systems
The leaders of JSC “NPO VEI Elektroizolyatsiya” being the members of Study Committee A1 “Rotating Electrical Machines” took part in the discussion on the following questions:
Developments of rotating machines and experience in service
– design, manufacture, maintenance of generators, excitation systems and pumped storage units
– impact of the requirements of customers and grid operators on the design of generators and their characteristics. New directions of development for improvement of parameters, design, cost properties and flexibility of management of large generators
– efficiency, operation and development of engines for power plants and distributed generation
Asset management of rotating machines
– experience in upgrading, replacing, increasing the power and efficiency of retired generators and cost-benefit analysis of projects
– state of technological equipment and the experience of inspection with the help of robots
– improvement of monitoring, diagnostic and forecasting systems
Rotating machines for renewable and dispersed generation
– design, manufacture, cost of generators, efficiency, monitoring and diagnostics
– effect of damages and system disturbances on design and management strategy
– evolution and trends in machinery for renewable generation.
Within the framework of the company’s key competencies, among the reports presented at the Session, the following works attracted professional interest of JSC “NPO VEI Elektroizolyatsiya”:
- Brazilian Experience with Development and Deployment of an Online PD Monitoring System on Rotating Machines Based on Virtual Instrumentation A.T. CARVALHO, H.P. AMORIM, F.S. BRASIL, P.R.M VILHENA, D.S. CARVALHO – BRAZIL A1-201
Despite the fact that one of the most effective methods for diagnosing a rotating machine is the method of partial discharges measurement, it has not been widely used in hydroelectric power plants in Brazil because of the complexity of the technology, the lack of qualified personnel for its interpretation, and the high cost of measuring instruments and systems continuous monitoring. To meet this challenge, Cepel and Eletronorte, a subsidiary of the Brazilian energy company Eletrobras, a representative of generation, transmission and distribution of electric power in the territory of the Amazon states, have tested a partial discharge monitoring system based on virtual measuring instruments using digital IMA-DP technologies. The authors distinguish such features of the virtual measurement system as: measurement in the HF band (frequency range 3-30 MHz), sequential monitoring of all channels, control of three-phase circuits, flexible number of channels, standardization of measurement results and availability of a database, centralized analysis of machines and measurement points , the allocation of points of special observation, connection and correlation with other monitoring systems. The work presents the architecture of the measurement system, including virtual and modular measuring instruments, high-frequency switches, high-speed oscilloscopes, programmable gate array, controller, software.
The developed system is characterized by lower cost and greater flexibility to allow more qualitative measurements. The authors consider the development to be a basis for future monitoring of partial discharges.
- Progress in Interpreting On-line Partial Discharge Test Results from Motor and Generator Stator Windings H.G. SEDDING, G.C. STONE, V. WARREN – CANADA А1-202
For decades partial discharge testing has been performed to detect faults in the insulation of the stator winding in engines and generators, being an important tool for maintenance of equipment. A database has been accumulated for more than 400,000 tests on 15,000 machines (hydro generators and turbine-generators) around the world. The results of the statistical analysis of these tests show that the machine voltage class, cooling method, type of PD sensor, operating mode are important for the correct interpretation of the results while separation of noise interference. Partial discharge critical values that indicate problems in insulation are defined for various air-cooled and hydrogen-cooled machines. Comparison of partial discharge measurements with the database allows to determine the state of insulation without steady trend to be established and shows that the level of discharges for air-cooled machines is higher than with hydrogen cooling. Another advantage of the statistical approach is that the trend requires the operating conditions of the equipment be stable, within the IEEE 1434 and IEC 60034-27-2 standards.
- Assessment of manufacture quality of stator windings insulation of rotating machines by means of macrographic analysis. R.BAENA, S. RODRÍGUEZ, A. VILLARRUBIA B.REMARTINEZ, O. MARTINEZ – SPAIN A1-203
The authors consider micrographic analysis with the help of thin sections obtained from rods that have not passed the tests, as a method for controlling the main insulation of windings of electric machines. Iberdrola Generación conducts a micrographic analysis of electric generators insulation systems for more than two decades. With the introduction of digital visualization systems, the systematic analysis procedure described in the report was developed, implemented and are used in the procurement of new equipment, acceptance testing. The introduction of digital measuring technology eliminated the subjectivity of evaluations, allowed a detailed analysis of the structure, homogeneity of insulation, impregnation degree, the presence of voids, folds, etc. While micrographic analysis, the following measurements are taken: the presence and configuration of the inner corona protection, the inner and outer radius at the corners of the basic insulation, the thickness of the basic insulation at the corners and sides, the thickness of the winding conductors, the overlap tape, the range of the ribbon bend in the presence of wrinkles, the radius at the corners of the elementary conductors, the size of the voids in its presence.
The work of the Study Committee A3 “High voltage equipment” was focused on the following issues which are of JSC “NPO VEI Elektroizolyatsiya” interest:
High-voltage equipment for emerging power system conditions
– requirements for AC equipment, disconnectors, ground lead, measuring transformers
-requirements for DC equipment, incl. switches, disconnectors, ground lead, surge arresters / varistors
– development in the field of testing and inspection
Lifetime management of transmission and distribution equipment
– influence of environmental and operational conditions
– optimized maintenance procedures
– methods for overvoltages and overloads protection
Application of information technology tools for development and management of high voltage equipment
– advanced modeling and design tools
– integration of intelligence into high voltage equipment
– translation of data into useful information and actions.
- Environmentally Friendly Perfluoroketones-based Mixture as Switching Medium in High Voltage Circuit Breakers J. MANTILLA, M. CLAESSENS, M. KRIEGEL – SWITZERLAND А3-113
Currently, most of the gases and technologies offered as an alternative to sulfur hexafluoride for isolation and commutation have economic and technical limitations that hinder their use. But SF6 gas, widely recognized in the power industry for its unique insulation and switching capabilities, chemical inertness, non-flammability, has a direct impact on the environment, which is of concern to environmentalists. As an alternative to SF6 in standard SF6 high voltage circuit breakers, the authors of the report propose to use a mixture of perfluoroketones with CO2 and O2 with low environmental impact, summarizing the results of numerous switching tests. All experiments were carried out in a certified high-voltage laboratory of ABB (HPL) in Baden, Switzerland, in accordance with the requirements of IEC. The main explanation for successful switching is the formation of CF4 and C2F6 right after the arc, which are known to be an excellent gas medium for efficient switching. It was also found that the thermal interruptions during SLF are 20% lower than that of SF6. An interrupter rated at 60 Hz must be rated at 50 Hz with the same short-circuit current level, unless additional parallel capacitors are used. Unlike SF6, the large PFK molecules do not recombine after arcing, and the formation of toxic decomposition products is largely prevented due to the addition of oxygen. The PFK decomposition is not a limiting factor in terms of service life and overhauls periods when using a standard-sized CB tank.
Based on the test results, the mixture based on perfluoroketones, due to its chemical and thermodynamic properties, has a global warming potential of 1 with zero potential for depletion of the ozone layer, is non-flammable and is classified as practically non-toxic.
- Detailed analysis of livetanks, dead tanks and gas circuit-breakers using a new environmental friendly gas S. SILVANT, G. GAUDART, P. HUGUENOT, Y. KIEFFEL, M. PERRET, Ph. ROBIN-JOUAN, D. VIGOUROUX, R. FRAY, Y. CRESSAULT, Ph. TEULET, JY. TREPANIER – FRANCE- SWITZERLAND А3-114
The report is focused on the development of a new generation of circuit breakers based on a gas mixture known under the trade mark g. The use of new environmentally friendly gas has affected the design of the circuit breaker, modeling of arc breaking.
- Contactless thermal online-monitoring of electrical equipment under load to determine the load level and damage avoidance Т. GRÄF – GERMANY А3-204
Modern developments in the field of microelectronics make it possible to solve problems in the field of transmission and distribution of power, in particular, the report presents a system for the operational control of temperature measurements in electrical equipment at high voltage with the help of miniature non-intrusive devices with autonomous supply at certain points of equipment. One of the methods described shows the temperature measurement inside the switchgear. The second development is aimed at preventing explosions of HH-HRC fuses. The third technology is for measuring contact temperatures inside gas-insulated systems. In the first two cases, the temperature is measured in the operating mode in compliance with safety regulations without access to hazardous areas.
- D-Watch – intelligent disconnector mechanism for digital substation STELLA, M. PIVATO, J.L. RAYON – ITALY-FRANCE А3-205
The report focuses on the issues of intelligence entrance into high-voltage equipment, in particular, the use of a digital drive for pilot projects of high-voltage disconnectors for 145 kV, 245 kV and 420 kV grids in terms of state control, diagnostics and maintenance techniques. The authors consider the use of an electric drive operating by means a digital board, which allows the disconnectors to have embedded on-line monitoring functions of the mechanical process and a passive sensor to determine the temperature of the active part. DWatch allows you to maintain the real status of the equipment, which leads to obvious cost savings and increased reliability.
- Mathematical and physical models development for study the high-voltage resistive dividers of digital voltage transformers D. LEBEDEV, A.A. YABLOKOV, A.V. MAKAROV – RUSSIA A3-305
The article deals with the development and investigation of resistive voltage dividers (contain resistive elements in solid-state insulation). The authors analyze the influence of current-carrying elements of neighboring phases on the accuracy of measuring of optical voltage transformers. Methods for calculation of resistive voltage dividers, which allow choosing optimal parameters on the basis of analysis of thermal and electric fields are presented. The authors provide the results of studies of thermal fields, amplitude-frequency and phase-frequency characteristics of the experimental sample of a resistive voltage divider.
The work of Study Committee B3 “Substations” was devoted to the following issues:
Advances in substation technology
- developments of gas-insulated circuit breakers and lines, including direct current technologies
- integration of non-traditional measuring transformers
- introduction of new materials and technologies at substations
Developments and new thinking in substation design
- implementation of IEC 61850 on existing substations
- improving the operational readiness of substations
- solutions for modular, complete, rapidly deployable and marine substations
- adaptation of substations to new requirements for power systems
Evolution in substation management
- measurement of risks and optimization of decision making, substation economics, maintenance organization
- interaction of clients and shareholders in the design and management of the life cycle
- performance indicators, residual life, serviceability and condition of substation equipment.
The reports of Study Committee B3, presented at the 46th Session, are of JSC “NPO VEI Elektroizolyatsiya” scientific interest:
- High Power Underground Transmission for HV DC KOCH, D.IMAMOVIC, B.LUTZ, K.JUHRE, T.NEIDHART, R.-D. ROGLER – GERMANY В3-104
The report presents the technology of gas insulation for DC transmission, as well as the design, the physical and electrical aspects of the construction of the compact power transmission line HVDC.
- 170 kV pilot installation with a ketone based insulation gas with first experience from operation in the grid T.DIGGELMANN, D.TEHLAR, P.MUELLER – SWITZERLAND В3-105
The authors consider a pilot project of the use of a gas mixture C5 PFK as an alternative to SF6 gas at a 170 kV substation in Zurich, Switzerland. The physical properties, the chemical composition of the new alternative gas mixture, its advantages are described. The emphasis is on environmental friendliness due to the reduction of the negative impact on the environment (reduction of the carbon emission factor).
- Application of a fluoronitrile gas in GIS and GIL as an environmental friendly alternative to SF6 GAUTSCHI, A.FICHEUX, M.WALTER, J.VUACHET – SWITZERLAND-FRANCE В3-106
Modern science is aimed at search for a green alternative to SF6 gas for high voltage switchgears. The authors consider the results of the use of a g3 gas mixture consisting of a C4F7N fluoronitrile molecule based on the CO2 background gas in 145 kV switchgears and 420 kV gas-insulated lines. The tests confirm the ecological purity of g3 in comparison with SF6 gas.
- Development of common technical requirements for monitoring and diagnostic systems to improve availability of substations L.A. DARIAN, R.M. OBRAZTSOV – RUSSIA B3-213
The authors describe the results of joint work aimed at systematization and generalization of disparate technical requirements for Automated Monitoring and Diagnostic Systems (ASM & D) of certain types of high-voltage substation equipment in the Russian Federation – power transformers, high voltage circuit breakers, measuring transformers, switchgears, overvoltage limiters, cable couplings, GIL. The report can be considered as the first step in creating the regulatory and technical basis for the ASM & D of high-voltage equipment and the substation as a whole, in view of current trends in online monitoring of the technical condition of equipment in order to improve the manageability of substations.
The reports of the Study Committee C6 “Distribution Systems and Dispersed Generation”, in the areas – 1) integrated planning and operation for upgrading distribution networks, 2) energy infrastructure for urban networks, 3) micro grids and off grid hybrid systems – for JSC “NPO VEI Elektroizolyatsiya” professional interest are the following:
- Smart Region – Automation of Distribution System Z. MÜLLER, Z. POKORNA, S.HES – The CZECH Republic C6-306
Smart Region is a project implemented by ČEZ Distribuce (DSO) in the northern part of the Czech Republic. It is focused on automation of the power distribution system. The objectives of the project are to assess the capabilities of automation equipment in the new infrastructure and upgrade network management systems in order to optimize the operation of MV, LV networks.
- Battery Energy Storage Control Strategies for Deterministic and Stochastic Power Profiles A. OUDALOV, A.RIGAS, C. MAHIEUX – SWITZERLAND C6-307
The report considers a semiempirical model of aging (cyclic and calendar) lithium-ion batteries. It is established that to reduce aging, the state of charge (SoC) is important. However, due to energy constraints and internal losses, restoring Soc charge status to the reference range is necessary for performing battery functions. The authors offer several schemes for controlling the state of charge, and their effectiveness is estimated in a predictable and stochastic power storage system. The results show that the potential to extending the service life are application dependent, based on the degree of flexibility allowed by a service.
- Smart grids for rural conditions and e-mobility – Applying power routers, batteries and virtual power plants V. BUEHNER, FRANZ, J.HANSON, R.GALLART, S.MARTINEZ, A.SUMPER, F.GIRBAU-LLISTUELLA – GERMANY-SPAIN C6-308
The authors describe two pilot projects in the field of grid intellectualization, implemented in Europe Well2Wheel and Smart Rural Grid. The necessity of their implementation is justified by the grid operation in new conditions due to the development of renewable energy sources and the growing demand for electric transport, which causes grid instability (overload, voltage, deviation), especially in rural distribution networks. The link between these projects is the implementation of the same technology of a virtual power plant and the approach of cellular grid cells.
- The Hybrid Energy Storage System based on lithium-ion batteries and supercapacitors A.N. NOVIKOV, A.Z. ZHUK, K.K. DENSCHIKOV, N.L. NOVIKOV, T.YU, ZHORAEV, YU.N. KUCHEROV, E.A. BUZOVEROV – RUSSIA C6-310
The authors developed and tested a hybrid power storage system of 200 kW and energy capacity of 200 kWh to ensure the stability and sustainable operation of decentralized and non-traditional energy sources, both autonomously and in the structure of electric power systems. A bench was developed to test power storages with capacity of up to several megawatts. During the tests, a number of technical advantages of using the hybrid scheme and its economic efficiency were confirmed.