Date of Award

May 2017

Degree Type


Degree Name

Master of Science



First Advisor

Lingfeng Wang

Committee Members

Wei Wei, Weizhong Wang


As energy demand increases in U.S. society, especially in terms of electricity and water, it becomes crucial for the operator to ensure the reliability and security of power distribution systems and wastewater treatment facilities. In the past, deterministic approaches were developed in evaluating the reliability of power supply systems. However, deterministic approaches lack the stochastic characteristic modeling, which makes it ineffective in modeling practical systems with increasing uncertainties. In this thesis, a set of probabilistic, quantitative reliability indices will be calculated for the active power distribution networks and wastewater treatment plant (WWTP) electrical supply systems.

First, the probabilistic reliability evaluation for active distribution networks is performed. Due to the higher pressure from the environment, the integration of renewable resources and application of storage units has become more prevalent in the past several decades. Consequently, using the conventional deterministic approach to evaluate the reliability of active distribution networks may not be effective anymore. In this thesis, a new method is proposed to evaluate the active distribution system reliability containing microgrid and energy storage. The power output of distributed generator (DG) within the microgrid is first calculated based on the approach of generalized capacity outage tables (GCOTs). Then, the Monte Carlo Simulation (MCS) is utilized for performing power system reliability evaluation. The results obtained considering different energy storage capacities are compared. Furthermore, real-time pricing strategy is incorporated in optimizing the control strategy of the storage device. The reliability indices are then recalculated to inform the system operator in power system planning and operations.

Second, the probabilistic reliability evaluation for WWTP electrical supply systems is conducted. Due to the rapid development of industry development and population growth, the electrical power supply system in WWTPs also demands a more comprehensive reliability evaluation, which is currently treated as a mechanical reliability problem in the wastewater treatment industry. In fact, the electrical part also plays an essential role in ensuring the availability and reliability of WWTPs. In this thesis, reliability evaluation mainly focuses on the electrical power supply system instead of the mechanical equipment. Furthermore, the Intelligent Power Motor Control Center (IPMCC) model is incorporated, which is widely used in WWTP control systems. A time-sequential MCS simulation method is used to derive the system reliability indices, and several other techniques are also utilized including the reliability model of IPMCC and the load based reliability indices calculation.

A comparison is conducted between the reliability analyses of active distribution system in power systems and the electrical supply system of WWTP. In fact, both systems do have some similarities, such as the component reliability model and the evaluation procedure. However, in terms of some specific characteristics of each system, reliability modeling and evaluation methods may need some changes correspondingly.