An improved approach for the assessment of utility and customer harmonic contributions in unbalanced power networks

Today's power networks, with advancement in technology, there is an increase in the harmonic content in power networks. Although these advancements provide more efficient solutions to researchers and industrialists, the harmonic disturbances they cause need to be dealt with. The harmonic currents injected by a single customer may create an impact on the quality of power delivered to other neighbouring customers. Therefore, the assessment of harmonic contribution is very important for sensitive load facilities such as nuclear and radiological facilities, whose safety and operating systems are adversely affected by harmonic distortion such as costly equipment breakdown and facility shutdown. The main contribution of harmonics reflects through additional component of power that is known as fictitious power. Unfortunately standard power meters, including modern smart meters, do not register this component. Accordingly, utilities suffer huge losses. As we, and other authors, proved this component of power cannot be neglected. In addition, harmonics will produce indirect losses to the utility due to malfunction in other power network equipment. It is necessary to upgrade the meters with the possibility to register all components of harmonic power component. Otherwise the customers will not take care about the level of nonlinearity of their load. In contrast, they will be stimulated to use harmonic mitigation devices that reduce their bills.As a result, it is important to determine who is the real responsible of harmonic distortions. This way, it would seem logical to determine responsibilities: those corresponding on the one hand to the utility, and on the other hand to the customer. The main problem that prohibits finding the comprehensive solution lies in disagreement within the power engineering community on the best definition of the harmonic pollution level. Using the Total Harmonic Distortion (T H D) factor as an indicator is not sufficient for analyzing the effects of the harmonic pollution in the power network. Namely, T H D only defines how much the waveform of current/voltage is distorted and does not give information about the nominal power of the load. Disadvantages of T H D bring into focus finding other ways to define a Power Quality Index (P Q I). The problem with detecting the source of harmonic pollution becomes very urgent and should be solved as soon as possible. Still, there is no standard procedure or method with which this problem can be easily resolved. A great deal of attention has been placed on identifying harmonic sources in power networks. Formulation and implementation of accurate and robust methodologies for the assessment of harmonic pollution in modern power networks is important from the two main points of view. The first is determining the harmonic contribution for each power harmonic order. The second is establishing suitable regulatory frameworks, incentives and policies for a fair and correct allocation of responsibilities and roles in mitigating possible power quality problems. Therefore the author of this thesis motivated to provide a solution that could be implemented as an upgrade to revenue meters, which comes through the ability of a proposed method to determine harmonic distortion responsibility on the power network and provide the utility with necessary data to take appropriate action. This action may include the design of an appropriate mechanism to mitigate or cancel the effects of the harmonic injections or penalising those responsible.