The reactive power and voltage level control in distribution networks are routine in a power. The customer s voltage levels legislation, allows to the customers with voltage levels out of the limits stipulated by Brazilian Electricity Regulatory Agency receive financial compensation by inadequate service. The coordinated adjust of the equipment, capacitor banks and voltage regulators allocation along the feeders are usual actions to ensure proper voltage levels to the customers. In Brazil, distribution networks are usually large with numerous and long low-voltage circuits. Based on the networks geo-referenced registers, the proposed algorithm uses computational intelligence techniques to optimize voltage levels and reactive power, considering the primary and secondary network distribution. This work provides a tool that will allow the specialist obtain the most cost-effective to simultaneous capacitor banks and voltage regulators allocation, optimizing the primary and secondary voltage levels in distributions networks, minimizing operating costs and losses. / O controle do perfil de tensão nas redes de distribuição é uma tarefa rotineira em distribuidoras de energia. Com uma legislação rígida sobre os níveis de tensão, as unidades consumidoras que estão com o fornecimento fora dos padrões estipulados pela ANEEL (Agência Nacional de Energia Elétrica) recebem compensação financeira pelo serviço inadequado. O ajuste coordenado dos equipamentos e a alocação de banco de capacitores e reguladores de tensão ao longo dos alimentadores são ações práticas para garantir níveis de tensão adequados aos consumidores. No Brasil, as redes de distribuição são longas com inúmeros circuitos de baixa tensão igualmente extensos. Tendo como base o cadastro georeferenciado das redes, o algoritmo proposto neste trabalho utiliza técnicas de inteligência computacional para otimizar os níveis de tensão e reativos no sistema de distribuição, considerando as redes primárias e secundárias de distribuição. Este trabalho traz uma ferramenta que permitirá ao especialista obter a melhor relação custo-benefício na alocação simultânea de bancos de capacitores e reguladores de tensão, otimizando os níveis de tensão nas redes primárias e secundárias, minimizando custos operacionais e perdas.

<p>Doktorskom disertacijom je dokazano da postojeće metode detekcije i identifikacije loših podataka nisu primenjive na distributivne mreže usled njihovih specifičnosti u stepenu redundanse merenja i broja pseudo merenja. Dodatno, razvijeni su algoritmi detekcije loših oblasti primenom dekuplovanog Hi-kvadrat testa, identifikacije loših merenja primenom novo definisanih izbeljenih reziduala, estimacije fazne konektivnosti primenom uslovnih ograničenja u estimatoru stanja, i korekcije pseudo merenja primenom informacija sa pametnih brojila. Navedeni algoritmi su specijalizovani za distributivne mreže i verifikovani primenom na dva test sistema.</p> / <p>The doctoral dissertation has demonstrated that conventional bad data detection and<br />identification methods cannot be efficiently applied in distribution networks, due to<br />their characteristics such as low measurement redundancy, number of pseudo<br />measurements and level of measurements correlation. In addition, the doctoral<br />dissertation described newly developed algorithms for bad area detection based on<br />decoupled Chi-squares test, bad data identification using newly defined whitened<br />residuals, estimation of phase connectivity by extension of state estimation with<br />conditional constraints and correction of pseudo measurements using AMI data. The<br />mentioned algorithms are specialized for distribution networks and verified through<br />simulation on two test systems.</p>

The increasing levels of renewable generation and the electrification of transport and heating as parts of the movement towards low-carbon energy systems to cope with climate change will place significant challenges on the electricity system to facilitate the way towards future low carbon energy systems in a cost effective way and ensure secure power delivery. New solutions and higher levels of flexibility are required than currently exist in order to reduce the integration costs of low carbon generation and demand technologies. Price-based demand response in residential sector is considered as one of these potential solutions. However, a certain level of automation is required to reduce both the uncertainty in the consumer response and the complexity for consumers to react to the price signal. This thesis presents a comprehensive and general residential optimization-based Automated Demand Response (ADR). The modelling of home appliances has been extensively developed to include all the classifications proposed in the literature, namely, deferrable and thermal in addition to new groups of critical and fully curtailable loads. The operations of the appliances are controlled in response to dynamic price signals to reduce the consumer’s electricity bill whilst minimizing the daily volume of curtailed energy and therefore considering the user’s comfort level. To avoid shifting most portion of consumer demand towards the least price intervals, which could create network issues due to loss of diversity, higher prices are applied when the consumer’s demand goes beyond a power threshold level. The arising mixed integer nonlinear optimization problem is solved in an iterative manner rolling throughout the day to follow the changes in the anticipated price signals and the variations in the controller inputs while information is updated. The results from different case studies show the effectiveness of the proposed controller to minimize the household’s daily electricity bill while preserving comfort level as well as preventing creation of new least-price peaks. This thesis also proposes a two-stage distribution-planning framework to assess the benefits of the proposed ADR models in response to a location-specific time of use Distribution Use of Systems Charge (DUoSC) on the required investments to connect future low-carbon technologies. The network investments and the satisfaction of consumers in terms of energy curtailment are both quantified. The first stage aims to generate location-specific time of use price signals for all users in the network, which represents their contributions in future network investments due to congestion and security constraints. The second stage relates to a group of ADR controllers at residential premises that aims to minimise the daily energy payment whilst maximising consumer comfort in response to the corresponding price signal produced from the first stage.

Dans le futur, les réseaux de distribution deviendront intelligents et actifs et seront utilisés au plus près de leurs limites car l'avènement de la dérégulation avec l'introduction massive de la production décentralisée induira une optimisation des infrastructures de l'énergie pour des besoins environnementaux d'une part, mais aussi par l'introduction de la concurrence dans un secteur autrefois monopolistique. Si on veut utiliser pleinement le potentiel des productions décentralisées dans les réseaux de distribution, on devra rendre ces réseaux observables au moyen de mesures qui seront intégrées dans les systèmes de supervision et de contrôle car sans observabilité et reconstruction d’état du réseau, le contrôle du réseau est impossible. Pour un grand réseau de distribution (quelques milliers de nœuds), avec un taux d’insertion important de productions décentralisées, l’observabilité en temps-réel devient très difficile. Dans la littérature scientifique, on ne trouve pas de travaux prenant en compte les réseaux intelligents et reconfigurables de demain avec production décentralisée massive. L'enjeu du projet sera donc de développer des algorithmes de reconstruction d'état prenant en compte les spécificités des réseaux du futur, à les valider et à les intégrer dans les outils de gestion des réseaux du distributeur. La reconstruction d'état permettra d'aider à l'automatisation et donc à l'introduction d'intelligence dans les réseaux de distribution du futur ainsi qu'à l'insertion massive de productions décentralisées.________________________________________ / In the future, distribution networks will become intelligent and active and will be operated as close as possible to their limits, with the advent of deregulation and with the introduction of mass production that will lead to a decentralized infrastructure, this will guide to an optimization of energy for environmental issues in one side, but also to the introduction of competition in a sector once monopolistic. If the potential of distributed generation in the distribution networks is to be fully exploited, we will make these networks observable through measures which will be integrated into supervision systems and control, because without observability and reconstruction of network status, control network is impossible. For a large distribution network (a few thousand nodes), with an important quantity of distributed generation, real-time observability becomes very difficult. In the scientific literature, there is no work taking into consideration intelligent networks and reconfigurable of the future with decentralized mass power generation. The challenge of the project will be to develop algorithms of reconstruction of the state of the network, taking into account the characteristics of the networks of the future, to validate and integrate them into management tools distribution networks. The reconstruction of the state will assist in the automation and hence the introduction of intelligence in the distribution networks of the future and the insertion massive distributed generation.

ABSTRACT This thesis is concerned with a technical modification of design of the electrical power systems for Modřice and its surroundings. The thesis describes a basic theoretical distribution of the electricity network and the distribution network itself. Following chapters are devoted to the development and construction of the HV networks and to the methods and ways of calculating the steady operation of the network. These methods are then used in the computational programs that are presented in the next chapter of this paper. The aim of the practical part of the thesis is to first determine the current state of the network in the given location. Furthermore, several modifications are proposed according to the requirements for increasing the power consumption or connecting the new supply places. The proposed modifications are further assessed for the different operating conditions. The result is a network that is functional, operational and reliable. The whole analysis is carried out in the PAS DAISY Off-line V4 Bizon computing program.

Cette thèse étudie l'interaction technico-économique entre véhicules électriques et réseaux d'électricité. Le développement récent de la mobilité électrique invite en effet à analyser les impacts potentiels de la recharge de ces véhicules sur les réseaux électriques, mais aussi le soutien que ceux-ci pourraient apporter dans les réseaux du futur. Ce travail s'inscrit résolument dans le cadre des réseaux d'électricité intelligents ; la plupart des résultats de cette thèse s'appliquent tout aussi bien à un lave-linge, un chauffe-eau, une télévision tant que l'on leur prête la capacité d'intelligence ! Dès lors que les décisions des consommateurs électriques flexibles interagissent, ce cadre d'étude offre un terrain de jeu propice aux outils de théorie des jeux. Ceux-ci ont un apport direct lorsque le problème considéré a un fondement stratégique, mais leur application permet aussi de proposer des solutions sur des aspects où la théorie des jeux n'est pas forcément attendue : algorithmique, dans l'échange d'information entre acteurs, etc. La description de cet apport est l'objet principal de ce travail de thèse et se décompose en trois parties. En fil rouge, le cas des profils de charge rectangulaires – soutenus par de nombreux arguments pratiques mais souvent délaissés par les chercheurs – est analysé. En premier lieu, des questions algorithmiques se posent pour coordonner la charge de véhicules électriques dans un même périmètre du système électrique. Proposant et étudiant un algorithme de coordination, il est montré comment les propriétés fondamentales de celui-ci - sa convergence, l'efficacité de ses points de convergence – peuvent être déduite d'un jeu auxiliaire sous-jacent. L'analyse de ce jeu est faite en montrant qu'il appartient à la classe des jeux de potentiel, sous des hypothèses physiques et économiques très générales. Sur le plan de l'échange d'information, un modèle est proposé pour réfléchir à la bonne communication entre un opérateur du réseau et un véhicule. Ces deux agents ont intérêt à communiquer pour planifier la charge intelligente du véhicule électrique, mais ont des objectifs distincts. Ce cadre est très proche du Cheap-talk en théorie des jeux, mais aussi de la problématique de la quantification en traitement du signal. Ce travail tisse au passage des liens entre ces sujets. Il propose aussi une méthode pour que l'agent du réseau et le véhicule s'accordent hors-ligne sur un bon mécanisme d'échange d'information. Enfin, la théorie des jeux est appliquée dans un cadre plus habituel, pour analyser le jeu des acteurs. Ceci est fait quand des ensembles de véhicules de taille importante, vus comme des flottes, cohabitent avec des véhicules individuels. Ceci offre un terrain de jeu applicatif aux outils très récents des jeux composites. Dans ces trois directions de recherche, des simulations sont effectuées dans le cadre d'un réseau de distribution d'électricité, maille du système électrique qui pourrait vivre des impacts significatifs si la charge est non-coordonnée. En particulier, elles montrent la robustesse des méthodes proposées face aux incertitudes sur les données lorsque des profils de charge rectangulaires sont considérés. / This thesis studies the technical and economical interaction between electric vehicles and electrical networks. The recent development of electric mobility leads to the analysis of potential impacts of electric vehicle charging on the electrical networks, but also to the possible support that these particular electric consumers could provide in the future smart grids. In this direction, most of the results given in this thesis also apply to a washing machine, a water-heater, a TV, as soon as these equipments are capable of being smart! When the decisions of flexible electric consumers interact, the considered framework naturally offers a unique exercise area for the tools of game-theory. The interpretation is straightforward when the considered problem is strategic by definition, but these tools allow also shedding light on other aspects: algorithmic coordination, information exchange, etc. The description of the benefits of using game-theory in this context is the aim of this work. This is done according to three aspects. In these three directions, a particular attention is drawn to the case of rectangular charging profiles, which are very practical, but often ignored by the literature. First, algorithmic issues arise when coordinating the charging of electric vehicles in a same area of the electrical network. A charging algorithm is proposed and analyzed. This is done by studying an underlying auxiliary game. This game is proved to belong to the class of potential games under very general physical and economic assumptions. In turn, it inherits from the strong properties of this class of games, namely convergence and an efficiency result in the case of a large number of electric vehicles. Considering information exchange, a model is proposed to design a good communication scheme between an operator of the electrical system and an electric vehicle. Both agents have an interest in exchanging information to schedule optimally the charging profile of the electric vehicle but they do not share the same objective. This framework is closely related to Cheap-talk in game theory and to quantization in signal processing. Amongst others, this work explains interesting connections between both topics. Furthermore, a method, which is used offline, is given to obtain a good communication mechanism between both agents. Finally, game theory is used in its traditional form, studying the strategic interaction when groups of a large number of electric vehicles – seen as fleets – coexist with individual vehicles. This allows the application of the very recent concept of composite games. In the three parts of the work, simulations are conducted in a French realistic distribution network, which could be the first part of the electrical system severely impacted by a non-coordinated charging. This highlights the robustness of rectangular charging profiles against forecasting errors on the parameters of the models.

Harmonic propagation studies of public distribution networks require accurate models of aggregate residential customers (groups of customers) that simulate the harmonic emission of the multitude of household appliances in the network. Most of the present models were developed with the component-based approach, where models of individual household appliances are combined to build the model of multiple customers. This approach requires high amount of input data, like models of individual household appliances and detail information of customer behavior and device composition, which is usually not easy to acquire. However, with the increasing number of PQ-analyzers in the networks, the measurement-based approach is now more and more considered for the modeling of aggregate customers. The measurement-based approach uses measurements of the network in combination with top-down methodologies to obtain models of the aggregate customers. Compared to the component-based approach it has several advantages, like inherent consideration of the real operating changes of the individual household appliances, variation of customer behavior, effect of line impedances, cancellation and attenuation effects, etc. This thesis presents the development of a time-series stochastic model of the low-order harmonic emission of aggregate residential customers based on a top-down measurement-based approach. The model represents the daily variation of the harmonic magnitudes and phase angles. Besides, the model includes the representation of the harmonic unbalances, which is of great importance for the proper analysis of harmonic propagation in medium-voltage networks. The model is parametrized for German networks, but the methodology can be applied to find the models of other regions or countries.

In the new global and local scenario, the advent of intelligent distribution networks or Smart Grids allows real-time collection of data on the operating status of the electricity grid. Based on this availability of data, it is feasible and convenient to predict consumption in the short term, from a few hours to a week. The hypothesis of the study is that the method used to present time variables to a prediction system of electricity consumption affects the results.

Integrating the electrical and thermal community buildings' energy systems can play an important role in harvesting wasted energy resources and reduction of carbon emissions from buildings and electricity generation sectors. It also increases demand management flexibility by minimizing the curtailed electricity on the grid through electrified heating without increasing the electricity peak demand. The current work examines Integrated Community Energy and Harvesting systems (ICE-Harvest), a new generation of distributed energy resources systems (DERs). They prioritize the harvesting of community waste energy resources—for example, heat rejected from cooling processes and distributed peak electricity fossil-fuel-fired generators, as well as energy from curtailed clean grid electricity resources—to help in satisfying the heating demands of commercial and residential buildings. As such, ICE-Harvest systems provide a solution that can minimize greenhouse gas emissions from high-energy-consumption buildings in cold-climate regions such as North America and Northern Europe. In the current research, a thermal energy sharing model was developed to provide a dynamic characterization of the potential benefits of integrating and harvesting energy within a community of any number of buildings. The proposed model estimates the amount of rejected heat from cooling and refrigeration systems that can be simultaneously collected and used to heat other nearby buildings connected with a low temperature microthermal network (MTN). It also determines the proper timing and quantity of electricity used by the heat pumps in low-temperature MTNs as well as the reduction of both GHG emissions and the energy required from the EMC relative to conventional stand-alone systems. For an energy-balanced community cluster, the model showed that, over the course of a year, the energy harvesting would reduce this node’s GHG emissions by 74% and cover approximately 82% of the heating requirements compared to the BAU system. The results also revealed that the diversity in thermal demand between the connected buildings increases the harvesting potential. This research develops two clustering methods for the ICE-Harvest system. The proposed methods are clustering around anchor building and density-based (DB) clustering with post-processing by adding the closest anchor building to each cluster that focuses on the diversity of the buildings in each cluster. The energy sharing model is used to examine these techniques in comparison with the density-based clustering technique, the commonly used technique in the literature on a large database of 14000 high energy consumption buildings collected in Ontario, Canada. The results of this case study reveal that DB clustering with post-processing resulted in the largest emission reduction per unit piping network length of 360 t CO2eq /km/year. In addition, this research identified seven different cluster categories based on the total and simultaneous cooling-to-heating ratios of each cluster. The ICE harvest system integrates the thermal and electrical networks to add more flexibility to the electricity grid and schedule the electrification of heating (EoH). Current research provides a reduced model for the ICE-Harvest system to study its impact for over 1100 clusters of different categories on a provincial scale on the GHG emission and electricity demand from the grid. The use of ICE-Harvest systems at this scale can displace the energy required from the gas-fired heating resources by 11 TWh, accounting for over 70% of the clusters’ total heating requirements. This results in a 1.9 Mt CO2eq reduction in total GHG emissions, which represents around 60% of the clusters’ emissions. Operating conditions of the thermal network (TN) in the integrated community energy systems affect the ability to harvest waste energy and the reduction of GHG emissions as well as the electricity peak demand and consumption. In the current research, modeling of different thermal distribution network operating scenarios was performed for the different community energy profile clusters. These operation scenarios include low-temperature (fourth generation), ultra-low (fifth generation), a binary range-controlled temperature modulating thermal network operating between Low and Ultra-low temperatures (ICE-Harvest), and a new proposed scenario wherein a continuous range-controlled temperature modulating micro-thermal network. The continuous range-controlled temperature scenario shows the most benefits with the large implementation on the identified clusters. It adds more flexibility to balance the electricity grid as well as results in large GHG emission savings while controlling the increase in site electricity peak demand. The load profile of the cluster affects the selection of the most beneficial energy integrated system. This research shows that, for most of the heating-dominated clusters, it is better to employ the continuous range-controlled temperature TN with peak control and CHP on sites to serve the high heating demands along with short term and seasonal thermal storage. For the majority of balanced and /or cooling-dominated clusters, it is better to implement more carbon-free resources to the electricity grid or on-site that produce electricity but are not associated with heat such as wind, hydro, and solar PV panels. Parametric studies were performed in this research including changing the CHP size, the CHP utilization efficiency, and the grid gas-fired generators usage conditions to show their impact on the GHG emissions reduction from the clustered buildings. The analysis was implemented on a fleet of 1139 sites in Ontario and the results showed that the CHP size and operating hours have a measurable impact on GHG emission saving. The system can reach up to 58% and 66.5% emission savings of the total sites’ emissions with 93% and 39% operating hours respectively following the Ontario grid natural gas peaking power plants for the years of 2016 and 2017 with larger CHP sizes. The largest share of GHG emission saving in 2016 is by the CHP (61%) as opposed to 30% in 2017. The reduced models introduced in this research for the thermal energy sharing, the ICE-harvest system operation and sizing, and the MTN operation aid the investigation of the impact of the large implementation of the ICE-Harvest systems on the GHG emissions and electricity grid. / Thesis / Doctor of Philosophy (PhD)

[ES] La sectorización de las redes ha demostrado ser una metodología estratégica en la reducción de los volúmenes incontrolados fugados, considerado uno de los principales problemas a los que tienen que enfrentarse diariamente los gestores de los sistemas de distribución de agua. Su principal objetivo es facilitar la monitorización de las redes, dividiéndolas en subsistemas, sobre los que se puede realizar un mejor y más fácil control de las anomalías en el consumo y presión. Uno de los inconvenientes que presenta esta técnica recae en su diseño. No existe una solución única, sino que atiende a diversos criterios para realizarlo. De manera generalizada, este diseño se basa en la experiencia del propio diseñador, siguiendo criterios puramente prácticos y con procesos manuales de prueba y error, cuyo grado de dificultad está vinculado al tamaño y complejidad de la propia red. Esta tesis plantea una metodología sistemática para el diseño de la sectorización de una red de distribución de agua, según criterios energéticos, con el fin de facilitar la delimitación de cada uno de los sectores de la red. Como resultado, se obtiene una organización de la red en sectores buscando una optimización energética de la misma, de tal modo que posteriores técnicas de mejora, como es el caso de la gestión de presiones, se vean favorecidas. La sectorización ha resultado ser una técnica eficaz en la búsqueda de fugas. Sin embargo, como supone una pérdida de capacidad hidráulica y una merma en la calidad del agua, esta tesis se cuestiona el planteamiento de una técnica no intrusiva alternativa que logre los mismos resultados. Así, se propone el desarrollo de una metodología que localice las fugas centrada en la interdependencia de todos los elementos y en el empleo de sensores de caudal y presión. El trabajo pone de manifiesto que es posible sectorizar la red de tal manera que se consigan mayores beneficios para la misma. Ahora bien, también es posible el empleo de otras técnicas que no requieran el cierre de tuberías pero que desprendan soluciones similares. El empleo de una técnica u otra dependerá de cada caso, de los objetivos establecidos y de la política de trabajo de cada gestor. / [CA] La sectorització de les xarxes ha demostrat ser una metodologia estratègica en la reducció dels volums incontrolats perduts, considerat un dels principals problemes als quals han d'enfrontar-se diàriament els gestors dels sistemes de distribució d'aigua. El seu principal objectiu és facilitar la monitorització de les xarxes, dividint-les en subsistemes, sobre els quals es pot realitzar un millor i més fàcil control de les anomalies en el consum i pressió. Un dels inconvenients que presenta aquesta tècnica recau en el seu disseny. No existeix una solució única, sinó que atén diversos criteris per a realitzar-ho. De manera generalitzada, aquest disseny es basa en l'experiència del propi dissenyador, seguint criteris purament pràctics i amb processos manuals de prova i error, el grau de dificultat del qual està vinculat a la grandària i complexitat de la pròpia xarxa. Aquesta tesi planteja una metodologia sistemàtica per al disseny de la sectorització d'una xarxa de distribució d'aigua, segons criteris energètics, amb la finalitat de facilitar la delimitació de cadascun dels sectors de la xarxa. Com a resultat, s'obté una organització de la xarxa en sectors buscant una optimització energètica d'aquesta, de tal manera que posteriors tècniques de millora, com és el cas de la gestió de pressions, es vegen afavorides. La sectorització ha resultat ser una tècnica eficaç en la cerca de fuites d'aigua. No obstant això, com suposa una pèrdua de capacitat hidràulica i una disminució en la qualitat de l'aigua, aquesta tesi es qüestiona el plantejament d'una tècnica no intrusiva alternativa que aconseguisca els mateixos resultats. Així, es proposa el desenvolupament d'una metodologia que localitze les fuites d'aigua centrada en la interdependència de tots els elements i en l'ús de sensors de cabal i pressió. El treball posa de manifest que és possible sectoritzar la xarxa de tal manera que s'aconseguisquen majors beneficis per a aquesta. Ara bé, també és possible l'ús d'altres tècniques que no requerisquen el tancament de canonades però que desprenguen solucions similars. L'ús d'una tècnica o una altra dependrà de cada cas, dels objectius establits i de la política de treball de cada gestor. / [EN] The sectorization of networks has proven to be a strategic methodology in the reduction of uncontrolled leakage volumes, considered one of the main problems that water distribution system managers must face on a daily basis. Its main objective is to facilitate the monitoring of the networks, dividing them into subsystems, on which a better and easier control of anomalies in consumption and pressure can be performed. One of the drawbacks of this technique lies in its design. There is no single solution, but it is based on different criteria. In general, this design is based on the designer's own experience, following purely practical criteria and with manual trial and error processes, whose degree of difficulty is linked to the size and complexity of the network itself. This thesis proposes a systematic methodology for the design of the sectorization of a water distribution network, according to energy criteria, in order to facilitate the delimitation of each of the sectors of the network. As a result, an organization of the network in sectors is obtained, looking for an energetic optimization of the same, in such a way that later improvement techniques, such as pressure management, are favoured. Sectorization has proven to be an effective technique in the search for leaks. However, as it implies a loss of hydraulic capacity and a decrease in water quality, this thesis questions the approach of an alternative non-intrusive technique that achieves the same results. Thus, it is proposed the development of a methodology to locate the leaks focused on the interdependence of all the elements and the use of flow and pressure sensors. The present work shows that it is possible to sectorize the network in such a way as to achieve greater benefits for the network. However, it is also possible to use other techniques that do not require pipe closure but provide similar solutions. The use of one technique or another will depend on each case, on the established objectives and on the working policy of each manager. / Salguero Barceló, FJ. (2021). La sectorización basada en criterios energéticos como herramienta para la gestión hídrica de redes de distribución de agua [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/178235