Development of adaptive protection scheme for distribution systems with high penetration of distributed generation
TL;DR: In this paper, the effect of high DG penetration on protective device coordination is explored and an adaptive protection scheme is proposed as a solution to the problems identified, which is implemented on a simulated actual distribution feeder.
Abstract: Conventional power distribution system is radial in nature, characterized by a single source feeding a network of downstream feeders. Protection scheme for distribution system, primarily consisting of fuses and reclosers and, in some cases, relays, has traditionally been designed assuming the system to be radial. After connecting distributed generation (DG), part of the system may no longer be radial, which means the coordination might not hold. The effect of DG on coordination will depend on size, type, and placement of DG. This paper explores the effect of high DG penetration on protective device coordination and suggests an adaptive protection scheme as a solution to the problems identified. Results of implementation of this scheme on a simulated actual distribution feeder are reported.
Citations
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01 Jan 2011
TL;DR: It is demonstrated that in compact distribution grids voltage control problems and blinding of protection are not likely to occur and that false tripping and fault level have to be considered carefully.
Abstract: In today's distribution grids the number of distributed generation (DG) units is increasing rapidly. Combined heat and power (CHP) plants and wind turbines are most often installed. Integration of these DG units into the distribution grid leads to planning as well as operational challenges. Based on the experience of a Dutch distribution system operators (DSO), this paper addresses several possibilities to handle grid planning issues. Effects on voltage control, grid protection, and fault levels are investigated and described. These aspects are illustrated with the aid of simulations on an existing distribution grid. It is demonstrated that in compact distribution grids voltage control problems and blinding of protection are not likely to occur and that false tripping and fault level have to be considered carefully.
396Â citations
TL;DR: A microgrid protection scheme that relies on optimally sizing fault current limiters and optimally setting directional overcurrent relays is proposed, and is tested on two medium-voltage networks.
Abstract: Microgrids can be operated either grid-connected to reduce system losses and for peak shaving or islanded to increase reliability and provide backup power during utility outage. Such dual configuration capability imposes challenges on the design of the protection system. Fault current magnitudes will vary depending on the microgrid operating mode. In this paper, a microgrid protection scheme that relies on optimally sizing fault current limiters and optimally setting directional overcurrent relays is proposed. The protection scheme is optimally designed taking into account both modes of operation (grid-connected and islanded). The problem has been formulated as a constrained nonlinear programming problem and is solved using the genetic algorithm with the static penalty constraint-handling technique. The proposed approach is tested on two medium-voltage networks: a typical radial distribution system and on the IEEE 30-bus looped power distribution system equipped with directly connected conventional synchronous generators.
374Â citations
TL;DR: Protection schemes for renewable integrated power networks which includes distribution, transmission and microgrid systems are presented, which are experiencing dynamic fault currents and frequent changing network topologies.
Abstract: Among different sources of alternate energy, wind and solar are two prominent and promising alternatives to meet the future electricity needs for mankind. Generally, these sources are integrated at the distribution utilities to supply the local distribution customers. If the power generated by these sources is bulk, then they are either integrated at the distribution/transmission level or may be operated in an island mode if feasible. The integration of these renewables in the power network will change the fault level and network topologies. These fault levels are intermittent in nature and existing protection schemes may fail to operate because of their pre-set condition. Therefore, the design and selection of a proper protection scheme is very much essential for reliable control and operation of renewable integrated power systems. Depending upon the level of infeed and location of the renewable integration, the protection requirements are different. For low renewable infeed at the distribution level, the existing relay settings are immune from any small change in the network fault current from new incoming renewables. However, bulk renewable infeed requires modification in the existing protection schemes to accommodate the fault current variation from the incoming renewables. For bulk penetration of the renewable, the requirement of modified/additional protection schemes is unavoidable. Adaptive relaying and non-adaptive relaying schemes are discussed in the literature for protection of power networks, which are experiencing dynamic fault currents and frequent changing network topologies. This article presents a detailed review of protection schemes for renewable integrated power networks which includes distribution, transmission and microgrid systems. The merits and demerits of these protection schemes are also identified in this article for the added interest of the readers. The visible scope of advance protection schemes which may be suitable for providing reliable protection for dynamic fault current networks is also explored.
348Â citations
TL;DR: In this article, the authors proposed a power flow control between utility and microgrid through back-to-back converters, which facilitates desired real and reactive power flow between the utility and the microgrid.
Abstract: This paper proposes a method for power flow control between utility and microgrid through back-to-back converters, which facilitates desired real and reactive power flow between utility and microgrid. In the proposed control strategy, the system can run in two different modes depending on the power requirement in the microgrid. In mode-1, specified amount of real and reactive power are shared between the utility and the microgrid through the back-to-back converters. Mode-2 is invoked when the power that can be supplied by the distributed generators (DGs) in the microgrid reaches its maximum limit. In such a case, the rest of the power demand of the microgrid has to be supplied by the utility. An arrangement between DGs in the microgrid is proposed to achieve load sharing in both grid connected and islanded modes. The back-to-back converters also provide total frequency isolation between the utility and the microgrid. It is shown that the voltage or frequency fluctuation in the utility side has no impact on voltage or power in microgrid side. Proper relay-breaker operation coordination is proposed during fault along with the blocking of the back-to-back converters for seamless resynchronization. Both impedance and motor type loads are considered to verify the system stability. The impact of dc side voltage fluctuation of the DGs and DG tripping on power sharing is also investigated. The efficacy of the proposed control arrangement has been validated through simulation for various operating conditions. The model of the microgrid power system is simulated in PSCAD.
284Â citations
TL;DR: In this article, the authors proposed a protection strategy based on microprocessor-based relays for lowvoltage microgrids, which is to a large extent independent of the fault current magnitude and the mode of operation.
Abstract: One of the major challenges associated with microgrid protection is to devise an appropriate protection strategy that is effective in the grid-connected as well as islanded mode of operation. This paper proposes a protection strategy based on microprocessor-based relays for low-voltage microgrids. Further, the structure of a new relay enabling the proposed protection strategy is presented. One of the salient feature of the developed protection scheme is that it does not require communications or adaptive protective devices. Moreover, it is to a large extent independent of the fault current magnitude and the mode of operation. Transient time-domain simulation studies are conducted to demonstrate the effectiveness of the proposed protection strategy and its enabling relay, using the PSCAD/EMTDC software package.
280Â citations
Cites background from "Development of adaptive protection ..."
...In [ 5 ], an adaptive strategy has been proposed for protecting distribution systems with high penetration of DRs....
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...The strategy proposed in [ 5 ] is based on communications amongst the equipment, does not accommodate the islanded mode of operation, and is applicable only if the penetration of DRs is high....
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References
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16 Jul 2000
TL;DR: In this paper, the authors described a few of the issues that must be considered to insure that DG will not degrade distribution system power quality, safety or reliability, although some of these issues are common to low voltage distribution networks.
Abstract: Distributed generation (DG) has much potential to improve distribution system performance and it should be encouraged. However, distribution system designs and operating practices are normally based on radial power flows and this creates a special challenge to the successful introduction of distributed generation. This paper has described a few of the issues that must be considered to insure that DG will not degrade distribution system power quality, safety or reliability. This paper focused on radial systems, although some of the issues discussed are common to low voltage distribution networks.
1,316Â citations
Book•
21 Dec 2006
TL;DR: In this article, a review of basic design principles for distributed generation transformer, Reactor, and Shunt Capacitor Protection Bus Protection Motor Protection Line Protection Pilot Protection Stability, Reclosing, Load Shedding, and Trip Circuit Design Microprocessor Applications and Substation Automation Problems Index
Abstract: Prefaces Introduction and General Philosophies Fundamental Units: Per Unit and Percent Values Phasors and Polarity Symmetrical Components: A Review Relay Input Sources Protection Fundamentals and Basic Design Principles System-Grounding Principles Generator Protection/Intertie Protection for Distributed Generation Transformer, Reactor, and Shunt Capacitor Protection Bus Protection Motor Protection Line Protection Pilot Protection Stability, Reclosing, Load Shedding, and Trip Circuit Design Microprocessor Applications and Substation Automation Problems Index
796Â citations
Book•
01 May 2013
TL;DR: P.P. Anderson, a noted expert on power systems, presents an analytical and technical approach to power system protection, showing how abnormal system behavior can be detected before damage occurs, and points to effective control action to limit system outages.
Abstract: "In a world of huge, interconnected networks that can be completely blacked out by disturbances, POWER SYSTEM PROTECTION offers you an improved understanding of the requirements necessary for prompt and accurate corrective action.P. M. Anderson, a noted expert on power systems, presents an analytical and technical approach to power system protection. His discussion shows how abnormal system behavior can be detected before damage occurs, and points to effective control action to limit system outages.Advance your knowledge of power system protection through a better understanding of:Protective devices and controlsProtection conceptsTransmission protectionApparatus protectionSystem aspects of protective systemsReliability analysis of protective systemsPOWER SYSTEM PROTECTION is expressly written for practicing engineers and advanced graduate-level student engineers who need a comprehensive resource on the principles of power system behavior. This essential reference work provides new and advanced concepts for understanding system performance."
758Â citations
Book•
01 Jan 2000TL;DR: In this article, the authors present DG case and sensitive study business factors and their influence on DG value objectivity and bias in DG planning and evaluation recommendations and guidelines for DG planners.
Abstract: Distributed generation versus traditional power systems demand for electric power reliability and reliability evaluation planning and the planning process cost and economic evaluation reciprocating piston engine distributed generators gas turbine powered distributed generators fuel cell powered distributed generators renewable resource distributed generators energy storage for use with distributed generation distributed generation systems - planning and comparison basic DG case examples - what to include and how basic DG cases -modularity and reliability and cost basic DG cases - grid interconnection options basic DG cases - schedule and operating characteristics basic DG cases - reliability, maintenance and availability basic DG cases - renewable resource generation detailed DG case and sensitive study business factors and their influence on DG value objectivity and bias in DG planning and evaluation recommendations and guidelines for DG planners.
556Â citations
"Development of adaptive protection ..." refers background in this paper
...This makes it more economical to meet an increase of load by connecting DG to distribution feeders rather than expanding tansmission and distribution (T&D) facilities [ 9 ]....
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TL;DR: In this article, the authors focus on some technical aspects, but not on the impact on the quality of supply and on tariff signals, and they focus on the technical aspects only.
Abstract: The insertion of dispersed generation into existing electric power systems has a great impact on real-time operation and planning. Several uncertainties characterize the ability of the existing power system to integrate this form of generation, Hence, dispersed generation must be taken into consideration in power system performance so that operation and security are not disturbed. Dispersed generation increases the complexity of controlling, protecting and maintaining power distribution systems. This article focuses on some technical aspects, but not on the impact on the quality of supply and on tariff signals.
459Â citations
"Development of adaptive protection ..." refers background in this paper
...Hadjsaid et al. [ 11 ] show through a simple example that fault currents through protective devices would change after introduction of DG. They further suggest checking protection selectivity for each new connection of DG. However, this...
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