Probabilistic assessment of the impact of distributed generation and non-linear load on harmonic propagation in power networks

2023 IEEE Belgrade PowerTech

2023

Accurate estimation of harmonics in partially monitored power networks with uncertain, power electronics interfaced low carbon technologies can facilitate efficient planning and operation of future net-zero distribution networks. A recent study demonstrated a methodology for estimating harmonic distortions in partially monitored, typically radial, residential distribution networks. This study extends the general applicability of the harmonic estimation method to higher voltage meshed networks. The Morris screening method based harmonic variation sensitivity analysis, and the sensitivity method based on electrical distance were proposed in this study and were combined together to determine the optimal/minimum number and location of PQ monitors. Appropriate scaling factors were recommended as well. This solves the problem of sub-optimal selection of monitoring locations when harmonic distortion is not highly correlated with the voltage drop at buses in the meshed network. Different types of harmonic injections from nonlinear loads are fitted using Kernel non-parametric distribution and are estimated separately according to different load types. The approach is validated, and its accuracy and reliability were demonstrated on a highly interconnected (meshed) section of the power system.

Section: F Harmonic Estimationmentioning

confidence: 99%

Estimation of Harmonics in Sparsely Monitored Distribution Networks

Zhao

2023 IEEE Belgrade PowerTech

2023

“…Based on the types of the non-linear loads, the mean of the normal distribution varies, as given in Table 5. The harmonic current injection from DGs follows pre-set normal distributions as well, and the mean of the normal distribution is also given in Table 5 [30]. The standard deviation of the aforementioned normal distributions is set to 10% of the mean.…”

Section: Mitigation Of Harmonicsmentioning

confidence: 99%

On capability of different FACTS devices to mitigate a range of power quality phenomena

Liao

IET Generation, Transmission & Distribution

2017

Self Cite

This paper investigates the impact of different FACTS devices on critical power quality (PQ) phenomena including voltage sags, harmonics and unbalance from the perspective of both mitigation effect and potential negative impact. The FACTS devices, including SVC, STATCOM and DVR, are modeled in commercially available software PowerFactory/DIgSILENT to study their impacts on the critical PQ phenomena. Two control strategies, voltage regulation and reactive power compensation, are considered for STATCOM. For DVR, a PI-controller is developed for the purpose of voltage sag mitigation. The merit of the proposed controller is presented by the dynamic response of during-fault voltage and the capability of post-fault voltage recovery. The study is carried out on a large-scale generic distribution network. The impact of various devices on PQ phenomena is assessed using appropriate evaluation methodologies, and the results obtained with and without mitigation are presented and compared using heatmaps.

“…The ratio of the magnitude of the injected harmonic current to that of the fundamental component (used to model harmonic injection by nonlinear loads and generation) follows pre-set normal distributions. The mean values of the normal distribution used for different types of non-linear loads and various DGs (including PV and wind generators), not listed here due to space limitations, can be found in [25]. The standard deviation of the aforementioned normal distributions is set to 10% of the mean.…”

Section: Case Study a Network Settingsmentioning

confidence: 99%

Zonal Mitigation of Power Quality Using FACTS Devices for Provision of Differentiated Quality of Electricity Supply in Networks With Renewable Generation

Liao

Abdel-Rahman

IEEE Trans. Power Delivery

2017

Self Cite

Abstract--This paper presents the concept of provision of differentiated quality of electricity supply based on customers' requirements in distribution networks. To fulfill this concept, five new gap indices are proposed to reflect the satisfaction of the received power quality (PQ) performance compared to the thresholds which are set based on customers' requirements regarding the performance of individual PQ phenomenon or the aggregated PQ performance. Using these new indices as objective functions, an optimisation based mitigation strategy is proposed to carry out the strategic placement of different FACTS devices based on the analysis of PQ performance and sensitivity analysis. In this methodology, greedy algorithm is applied to search the optimal mitigation scheme in order to enable the provision of differentiated PQ levels. The feasibility of the proposed mitigation methodology is demonstrated using large scale generic distribution network. The advantages and disadvantages of using the proposed indices as the optimisation objective functions are also analysed in the paper.Index Terms-Quality of supply, power quality, mitigation strategy, FACTS devices. I. INTRODUCTIONower quality (PQ) issues continue to attract significant attention from both utilities and customers. Among PQ phenomena that attract the most attention are voltage sags, voltage unbalance and harmonics. Voltage sags cause frequent disruptions to industrial processes and malfunction of electronic equipment; voltage unbalance issues cause overheating, accelerated thermal ageing of equipment and reduction of efficiency of the load and overall network [1]; and harmonics (voltage distortion) cause thermal stress, insulation stress and load disruption to both power system equipment and customer's equipment [2]. These PQ phenomena result in substantial financial losses to both utilities and industries. Furthermore, the increasing level of penetration of intermittent, power electronics connected renewable resources, electric vehicles and other power electronics interfaced loads results in increasing variability of PQ in power systems. With more sensitive equipment/devices connected to the grids, it is essential to provide acceptable quality of supply as required by customers. To ensure this, a number of international PQ standards, e.g., EN 50160 and IEC 61000 series, have been set up to provide guidelines to utilities regarding the acceptable levels of PQ supply.In reality, requirements on PQ performance vary from area to area (e.g., commercial, residential and industrial areas), depending on the sensitivity of customers' processes and equipment to specific PQ phenomena. Considering different PQ requirements by different parties involved in electricity supply chain, costs associated with PQ mitigation and willingness to contribute to PQ mitigation by different market players, the idea of provision of differentiated levels of quality of supply to different customers in different zones is becoming more and more acceptable. This approach will improve the...