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The first part of the dissertation investigates cost experience in the US life and health insurance industry over the period 1998-2012. We generally test the difference in expenses among different distribution systems, which mainly consists of independent agency, broker, career agency, exclusive agency, and direct writing. We check to see if cost, revenue and profit efficiency differences are associated with different distribution methods. Cost, revenue, and profit efficiencies are estimated by Data Envelopment Analysis. Unlike the results in the property and liability insurance industry, the cost difference is insignificant among distribution systems. Results on cost efficiency and revenue efficiency support the market imperfection hypothesis, which says that the market imperfections such as entry barriers, price regulation, or search costs cause the coexistence of different distribution systems. The second part of the dissertation examines the relationship between mergers and acquisitions (M&As), and underwriting cycles in the P-L insurance industry. In a soft market, capital is relatively high. This leads to an increase in the number of M&A transactions and the probability that managers conduct non-value-increasing M&As. We test this proposition by analyzing the associations between volumes of M&A deals, and returns associated with M&As and underwriting cycle. The results show that the numbers of M&As are negatively related with the premium rate changes and positively related with changes in the combined ratio. We also find that the cumulative abnormal returns around the announcement date of M&As are smaller for the shareholders of insurer acquirers in a soft market. Even more, we find that the market reaction of M&As is less sensitive to agency problems in a hard market than in a soft market. / Business Administration/Risk Management and Insurance

While the idea of critical break rate of water distribution pipeline (defined as the break rate after which it is no longer economical to continuously repair) has been accepted in the literature and among the practicing engineers, the formula to obtain the critical break rate has remained elusive. In this dissertation, an equation for identifying the threshold break rate of a pipe is developed. The threshold break rate equation gives a rule of thumb for pipe replacement decision. Input parameters to obtain the threshold break rate of a pipe are repair and replacement costs, interest rate, and the length of the pipe. In addition, a methodology that enables the use of threshold break rate with the failure intensity and hazard functions is developed. The methodology is drawn by considering the relationships of the definitions of the threshold break rate with intensity and hazard functions in the context of a repairable system's failure process modeling. As a result, the newly developed threshold break rate equation can be coupled with any appropriate intensity and hazard function to obtain economically optimal replacement time of a pipe. Also, practical usage of the threshold break rate is demonstrated with a number of numerical examples. Design aids in the form of charts and tables are provided. The threshold break rate can be easily obtained either graphically or with the aid of the tables. The methodology that links the threshold break rate and failure rate (intensity and hazard) functions is extended to accommodate stress multiplying environmental factors in the form of the proportional intensity and hazards model. The two models consist of an age dependent failure rate function and a covariate structure. They are applied to a case study area pipe system to obtain optimal replacement times for individual pipes in the system. As a result, important hazard characteristics of water distribution pipes are drawn, and implications on the optimal replacement analysis are discussed. A pipe break prediction model is also developed in this research. The model spans the space between the linear and exponential break trends. The model is applied to the case study area pipe system with various cost options. The results from this analysis are discussed in terms of practical implementation of the replacement strategies. / Ph. D.

This thesis demonstrates the value of integrating electrical distribution engineering analysis with Geographic Information Systems (GIS). The 37-Node IEEE Feeder model was used as the base distribution system in this study. It was modeled separately, both in software capable of unbalanced load-flow and in an industry-standard GIS environment. Both tools utilized were commercially available, off-the shelf products indicative of those used in academia and in basic GIS installations. The foundational data necessary to build these models is representative of information required by a variety of utility departments for a multitude of applications. It is inherent to most systems within an enterprise-level, business-wide data model and therefore can be used to support a variety of applications. In this instance, infrastructure information is assumed to be managed and housed with the GIS. This data provides the required information as input for load-flow calculations. The engineering analysis is performed within DistributionSystem 4.01 and its output is passed back to the GIS in tabular format for incorporation. This thesis investigates the transfer of information between GIS and DistributionSystem 4.01 and demonstrates the extended display capabilities in the GIS environment. This research is implemented on a small scale, but is intended to highlight the need for standardization and automatic integration of these systems as well as others that are fundamental to the effective management of electrical distribution systems. / Master of Science

Yes / Electricity providers aims to deliver uninterrupted electrical services to their customers at minimum cost while providing a satisfactory quality service. Therefore, the power system reliability is essential in power distribution network planning, design, and operation. This paper proposes a novel mathematical model to improve the reliability of reconfigurable distribution networks via investing and operating tie-lines. While the failure is being repaired, tie-lines allow the network operator to transfer loads from failed zones to healthy zones. Constructing new tie-lines could improve the network’s flexibility, aiming to reduce the cost of expected energy not supplied (EENS). The objective function of the proposed method is a trade-off between the investment cost of tie-lines construction in the planning stage, the cost of tie-lines operation (e.g., opening/closing), and the cost of EENS in the operational stage. The model simultaneously evaluates the best combination of investments and network configuration for each contingency while considering network constraints. A multistage mathematical model is developed as mixed-integer linear programming (MILP) to overcome the computational complexity and maintain solver traceability for utility-scale realistic networks. The model can handle the network reconfiguration (NR) considering N-x contingency analysis in the operation stage while deciding the investment in tie-lines in the planning stage. The optimal investment and operation in tie-lines, according to numerical results, can reduce the cost of the Distribution System (DS) while responding with contingencies by 51 to 70%.

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Smart radial distribution grids will include advanced metering infrastructure (AMI) and significant distributed generators (DGs) connected close to loads. DGs in these radial distribution systems (RDS) introduce bidirectional power flows (BPFs) and contribute to fault current. These BPFs may cause unwanted tripping of existing overcurrent (OC) protection devices and result in permanent outages for a large number of customers. This thesis presents a protection approach that modified an existing overcurrent protection scheme to reduce the number of customers affected by faults in RDS with DGs. Further, a technique is presented that utilizes customers loading information from smart meters in AMI to improve the sensitivity of substation OC relays by adaptively changing the pickup settings. The modified protection approach involves predefining zones in RDS with DGs and installing directional OC relays and circuit breakers at the zonal boundaries. Zonal boundary relays determine faulted zones by sharing information on the direction of detected faults current using binary state signals over a communication medium. The technique to adapt the substation relay pickup settings uses the demand measurements from smart meters for two 12-hour intervals from the previous day to determine the maximum diversified demand at the relay?s location. The pickup settings of the substation relay for the two 12-hour intervals during the following day for the zone supplied by the substation are adaptively set based on the current that corresponds to the maximum diversified demand from the previous day. The techniques were validated through simulations in EMTP/PSCAD using an expanded IEEE 34 node radial test feeder that included DGs and a secondary distribution level. By decentralizing the control of the zonal boundary breakers, the single point of failure was eliminated in the modified protection approach. The cases studied showed that the modified protection approach allows for selective identification and isolation of the faulted zones. Also, the sensitivity of the substation OC relay was improved by at least 24% by using the pickup settings for the two 12-hour intervals from the smart meter demand measurements compared to the pickup settings computed using the conventional methodology based on the maximum loading of the zone.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-04-15T15:27:12Z No. of bitstreams: 1 ingridsoarespereira.pdf: 1591373 bytes, checksum: 3eaabd818bc093a00de802152356d2ea (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-04-24T03:19:52Z (GMT) No. of bitstreams: 1 ingridsoarespereira.pdf: 1591373 bytes, checksum: 3eaabd818bc093a00de802152356d2ea (MD5) / Made available in DSpace on 2016-04-24T03:19:52Z (GMT). No. of bitstreams: 1 ingridsoarespereira.pdf: 1591373 bytes, checksum: 3eaabd818bc093a00de802152356d2ea (MD5) Previous issue date: 2015-08-31 / Este trabalho apresenta uma nova abordagem para o problema de Estimação de Estados em Redes de Distribuição de Energia Elétrica utilizando os dados históricos de cargas e medidas obtidas pelos Sistemas de Medição Fasorial Sicronizada (PMUs – Phasor Measurement Units). Nesta formulação as tensões em módulo e fase são escolhidas como variáveis de estados e o problema é matematicamente formulado como um problema de otimização com restrições de igualdade e desigualdade. A função objetivo é formada pela soma quadrática dos resíduos de estimação, definidos como a diferença entre os valores medidos através das PMUs e os valores calculados. As restrições de igualdade são as injeções de potencia ativa e reativa nulas nas barras de passagem. As restrições de desigualdade estão associadas às potências ativas e reativas das barras não monitoradas, onde admite-se limites inferiores e superiores em função dos dados históricos das cargas (potências ativas e reativas). Estudos de casos são realizados utilizando-se um sistemas simples 10 barras, e os sistemas IEEE da literatura de 33 e 84 barras. Os dados de medições fasoriais foram obtidos utilizandose um programa computacional de cálculo de fluxo de potência. Os resultados da estimação de estados utilizando a metodologia proposta foram obtidos através de simulações no ambiente MATLAB e comparados com os resultados do programa de fluxo de potência para validação. A utilização de medição fasorial sincronizada nos entroncamentos e no final dos ramais do sistema de distribuição associada à utilização de restrições de desigualdade para as potências ativas e reativas das cargas não monitoradas são as principais contribuições deste trabalho. / This work presents a new approach to the State Estimation problem in Electrical Distribution Networks using historical data loads and measurements obtained by Phasor Measurement Units (PMUs). In this formulation voltage magnitudes and angles are chosen as state variables and the problem is mathematically formulated as an optimization problem with equality and inequality constraints. The objective function is formed by the quadratic sum of weighted measurements residues, which are defined as the difference between the PMU measurements and the calculated values. The equality constraints are defined as the zero injections of active and reactive power at the no load buses. The inequality constraints are associated with active and reactive powers of non-monitored buses, bounded by a given limit, superior or inferior in relation to historical data loads (active and reactive powers). Case studies are performed using a simple 10-bus test system, and the 33 and 84 buses IEEE test systems. The data phasor measurements were obtained using a computer program that calculates power flow. The state estimation results using the proposed methodology were obtained through simulations in MATLAB environment and compared with the results of power flow program for validation. The use of synchronized phasor measurement at the beginning and at the end of the lateral feeders of the distribution system associated with the use of inequality constraints for active and reactive power for the non-monitored loads are the main contributions of this work.

Automated fault location systems use power quality monitoring and circuit data to provide with a distance or impedance estimate to the fault. This can be used to avoid manual patrolling of the entire feeder in case of a main feeder lockout. It can also be used for circuits with repeated momentary interruptions to pinpoint the section of the circuit causing such problems. Self clearing sub cycle faults have been identified as the precursors of a number of sustained faults (requiring the operation of protective device) in utility distribution networks. The frequency of such incipient faults increases considerably as they are about to evolve into a full blown fault. This report proposes a modified and improved fault location algorithm that can be used to accurately identify sustained as well as temporary faults. The algorithm is based in the time domain and takes into account the arc voltage during a fault event. The proposed algorithm is developed, validated and applied to known distribution field data. Time domain simulation models are also used for validation purposes. The developed algorithm was observed to be very accurate when compared to other impedance based fault location algorithms proposed in the literature. Finally, sub cycle event identification and fault pre-location is proposed that can be very useful for electric utility operations. Highly accurate results were observed during this application study. For instance, a current waveform containing three incipient and one full fault event is shown in the figure given below. The estimated reactance to an incipient fault location is approximately 1.1 Ω. The fault location results obtained from the first three sub-cycle faults can be used to avert the final sustained fault event. / text

When designing urban water systems (i.e. water distribution and sewer systems) it is imperative that uncertainty is taken into consideration. However, this is a challenging problem due to the inherent uncertainty associated with both system loading requirements and the potential for physical components failure. It is therefore desirable to improve the reliability of each system in order to account for these uncertainties. Although it is possible to directly evaluate the reliability of a water distribution systems (WDS) (using reliability measures), the calculation processes involved are computationally intensive and therefore unsuitable for some state-of-the-art, iterative design approaches (such as optimisation). Consequently, interest has recently grown in the use of reliability indicators, which are simpler and faster to evaluate than conventional direct reliability methods. In this thesis, a novel measure (the RUF) is developed to quantify reliability in urban water systems with a view to enhance their robustness under a range of future scenarios (Policy Reform, Market Forces, Fortress World and New-Sustainability Paradigm). The considered four future scenarios were synthesized in the EPSRC supported multidisciplinary 4 year project: Urban Futures. Each investigated urban future scenario is characterised by a distinct household water demand and local demand distribution (emerging due to different urban forms evolving in future scenarios). In order to assess the impact of urban futures, RUF has been incorporated into Urban Water System (UWS) dynamic simulations for both WDSs and Foul Sewer Systems (FSSs) using open source codes of EPANET and SWMM. Additionally, in order to overcome extensive computational effort, resulting from the use of traditional reliability measures, a new holistic reliability indicator, the hydraulic power entropy (IHPE) has been developed and compared to existing reliability indicators. Additionally, the relationship between the new reliability indicator and the above mentioned RUF reliability measure is investigated. Results suggest that the magnitude of the IHPE in network solutions provides a holistic indication of the hydraulic performance and reliability for a WDS. However, the performance of optimal solutions under some Urban Futures indicates that additional design interventions are required in order to achieve desired future operation. This thesis also proposes a new holistic foul sewer system (FSS) reliability indicator (the IFSR). The IFSR represents sewer performance as a function of excess pipe capacity (in terms of available increase and also decrease in inflow). The indicator has been tested for two case studies (i.e. different sewer network layouts). Results suggest that the magnitude of IFSR has positive correlations with a number of identified key performance indicators (i.e. relating to capacity, velocity, blockages). Finally, an Integrated Design Approach (IDA) has been developed in order to assess the implications of applying design interventions on both a WDS and downstream FSS. The approach holistically considers present and future operation of each interconnected system. The approach was subsequently demonstrated using two proposed design interventions. Results suggest that, for the considered design interventions, there is trade-off between the simultaneous improvement of both WDS and FSS operation and reliability.