DMS - basis for increasing of green distributed generation penetration in distribution networks

Vladimir Strezoski, Dragan Popovic, Dusko Bekut, Goran Svenda
2012 Thermal Science  
Modern (electric power) distribution utilities are faced with high penetration of distributed (electric) generation. Renewable generation is of prime interest. Within this generation, the green one incorporating solar (photovoltaic) and wind generation is the most important. Consequently, the following two imperatives are established in modern distribution utilities: (1) absorption of as much of available (connected to network) green generation as possible and (2) increasing of the limit of
more » ... n distributed generation penetration. This generation is a significant basis of Smart Distribution Grid Concept. Distributed generation transfers passive distribution network into active one. The active distribution network analysis, control, operation management and planning become significantly complex. This complexity radically hinders the achievement of two above stated imperatives referring to the distributed generation penetration. This paper proves that Distribution Management System is a unique powerful system that integrates all tools necessary for surpassing main difficulties in the achievement of the both imperatives. The proof is obtained by the elaboration of a set of power applications (mathematical calculations) integrated in the Distribution Management System. The most important power applications, which deal with voltage/reactive power control, are specially stressed. The penetration of DG in distribution networks changes the network nature from passive to active. Analysis, control, operation management and planning of an active distribution network become significantly complex. Independently of this complexity, the following two imperatives referring to GDG penetration are established in modern distribution utilities: (a) Absorption of the GDG production -absorption of as much of the available (connected to network) GDG production as possible, (b) Increasing of the GDG penetration limit -increasing of the limit of new GDG integration into distribution networks to the maximal extent. The higher the DG penetration is, the higher the level of DG influence on network operation is. The network voltage profiles rise (over the upper network voltage limits) is the most expressed influence of DG on distribution network operation. A great number of papers deal with this issue [1] [2] [3] [4] [5] [6] . In addition, DG influence short-circuit currents levels [4, 7] . This further influences breakers/fuses capacities and relay protection setting and coordination, as well as network relay protection concept. Mutual interference between DG penetration level and network (re)configuration, losses, harmonics and Combined Heat and (electric) Power (CHP) facilities operation are discussed in [8] [9] [10] [11] [12] , respectively. Service restoration after isolation of faulted part(s) of distribution network, in the presence of DG, is considered in [13] [14] [15] . Planning aspect (optimal allocation) of DG is considered in [4, 10] . The referenced papers do not exhaust all aspects of influence of DG penetration on distribution networks operation. But, they are sufficient to prove that the achievement of both above stated modern distribution utilities' imperatives is a very complex issue. Consequently, it is necessary to apply complex tools for dealing with this issue. The most complex DG are GDG due to their intermittent production. Thus, their importance and complexity are main motivation to emphasize them in this paper. The human experience and ad-hock rules (rules of thumb) are abandoned as tools for dealing with the issue of GDG penetration in distribution networks long ago [16] . Single line voltage drop compensation (SLVDC), which is provided by under load tap changing supply transformers (ULTCT) and voltage regulators (VR), as well as reactive power (var) resources [1, 17, 18] , are not sufficient for dealing with this very complex issue. DG production curtailment [2] is a tool that is contradictory to the first imperative referred to GDG penetration. As said above, the complexity of this issue is a consequence of the fact that GDG do not influence only voltage profiles of distribution networks. Their influence on short-circuit current levels, breakers/fuses capacities, relay protection setting and coordination, relay protection concept, optimal network configuration, losses, harmonics, CHP facilities operation, service restoration, network operation and development planning are also very significant aspects of GDG penetration. The complexity of the considered issue rises with the increase of the level of GDG penetration. The chapter Levels of GDG penetration defines seven levels of this penetration. These levels are in direct relation with the complexity of tools which are necessary to be applied for dealing with GDG. A huge number of computer tools for dealing with this issue are listed and discussed in [19] . These tools are more or less stand alone. Instead of applications of such a large numbers of stand alone tools, this paper proves that distribution management system (DMS) is a unique powerful system for surpassing main difficulties in the achievement of both above stated imperatives referring to GDG penetration. Practically all tools necessary for dealing with GDG penetration are integrated into DMS. Main DMS power applications (mathematical calculations), which are necessary for dealing with GDG penetration, are described in chapter DMS power applications. An application of DMS for dealing with GDG penetration in distribution networks is described in chapter Application of DMS. Due to lack of space in the paper, only the utilization of DMS Volt Control power application is specially stressed. It is shown that ULTCT and VR can be very effectively managed by DMS for the purpose of achievement of both imperatives referring
doi:10.2298/tsci120119071s fatcat:ybvhgy2245hcvjadasxwpzsak4