A New Assessment for the Total Harmonic Contributions at the Point of Common Coupling

Abstract

-A new method to determine the total harmonic contributions of several customers and the utility at the point of common coupling is presented. The proposed method can quantify the individual harmonic impact of each suspicious harmonic source at the point of common coupling. The individual harmonic impact index is then used to assess the total harmonic contribution of each harmonic source. This index can be calculated by the results processed from instantaneous harmonic voltage and current phasor values. The results demonstrate the performance of the proposed method in terms of steadystate accuracy and response to time-varying operating conditions. The proposed index can be used for billing purposes to control harmonic distortion levels in power systems.

A Novel Method for Assessing the Contribution of Harmonic Sources to Voltage Distortion in Power Systems

“…PCC voltages can be expressed by the superposition principle, but since all voltages in utility network and customers are complex vectors, an effective way to quantify the voltage contributions of utility and customers into a single value is needed. In [14] and [21], a method based on the scalar projection was introduced to quantitatively represent the harmonic contributions of utility and customers to PCC voltage distortion. Fig.…”

“…However, there is a need for a comprehensive evaluation method taking into account all harmonic orders. In [21], the total harmonic contribution(THC) was introduced based on the similar concept of THD as equations (32) and (33). The THC is defined as the ratio of all harmonic contribution voltages to the fundamental voltage contribution.…”

“…Three phase voltage and current can be decomposed into three symmetrical components of positive, negative and zero. Reversely, sequence components can be also transformed into phase voltage and current using quations ( 35) and (36) [21], [22]. Therefore, after transforming harmonic voltage and current for each harmonic frequency into balanced three sequence components, the harmonic contributions in the three sequence circuits can be assessed according to the procedure described above.…”

“…However, because harmonic source parameters and system operating conditions are not constant in real power systems, this assumption can lead large errors in the assessment. Several harmonic assessment methods based on recursive least square (RLS) algorithm were presented [21]- [23]. However, these methods have a potential 'wind-up' problem because the RLS algorithm uses constant forgetting factor.…”

Harmonic Distortion Contribution for the Transmission Loss Allocation in Deregulated Energy Market: A New Scheme for Industry Consumer

“…Generally, transmission losses commonly contribute between 3-5% of the total power losses in network [9]. Therefore, it is a major problem in the efficiency of generation cost.…”