IEEE Recommended Practice for Protection and Coordination of Industrial and Commercial Power Systems

Urban power transmission and distribution rely on safe operation of vast network of power cables. Majority cable insulation defects can result in partial discharge (PD), which is therefore a degradation mechanism as well as a good indicator of cable insulation condition. Previously published PD models, however, failed to help quantitatively evaluate the insulation condition, or they fail to help differentiate those in between the conditions which are safe to operate from those which may need urgent testing or inspection. PD mechanisms in power cables are reviewed first in this paper. Then a novel model which is based on F distribution is proposed aiming to classify the PD activities which may be associated with different level of degradation. This is based on previous reports that PD activities manifests differently when the levels of degradation of the defect site(s) progress. After that, the features and effects of the model are presented with a case study, and the model is verified by analyzing the waveform similarities. Finally, the nature of the model is compared with the abc-model and the dipole model, demonstrating that proposed model can uniquely recognize the three stages of PD defect development.INDEX TERMS Cable insulation, condition monitoring, partial discharges, abc-model, dipole model.

A Novel Model of Partial Discharge Initiation in Cable Insulation

Chen

et al. 2022

An Adaptive Overcurrent Coordination Scheme Withstanding Active Network Operations

Enrı́quez

Shih

2022

This paper aims to present a centralized adaptive protection scheme (APS) for the directional overcurrent relays (DOCRs) considering system dynamics such as load demand variations, topology changes and DGs to mitigate the above-mentioned effects. The scheme is suitable for different types of networks whether its radial or meshed. Afterall, it can determine the actual topology with the micro-PMUs and breaker status, automatically generate relay names accordingly with the topology bus locations, establish protection coordination pairs, coordinate DOCRs for parallel lines, identify transformers to offer backup operation for differential protection, perform load flow and fault studies, execute contingency and sensitivity analysis, and lastly, coordinate the DOCRs using differential evolution algorithm so that they always have the proper settings to operate in appropriate time providing selectivity. The performance of the proposed centralized adaptive overcurrent protection scheme is tested on the highly meshed IEEE 14 bus system. The proposed scheme has shown that it can adequately consider impacts of system dynamics and DG.

Protection Analysis of a Traveling-Wave, Machine-Learning Protection Scheme for Distributions Systems With Variable Penetration of Solar PV

Jimenez-Aparicio,

Patel,

Reno

et al. 2023

This work provides a detailed protection analysis of a fast, Traveling-Wave (TW), Machine-Learning (ML), local, non-directional, economic, and setting-less protection scheme. The goal is to provide an objective evaluation of how a data-driven TW protection scheme would perform when deployed on a power distribution system as a faster alternative to over-current (OC) protection. Fault simulations consider scenarios from none to high-penetration of renewable energy resources to show its suitability for future applications on Distributed Energy Resources (DER)-dominated distribution systems. A modified IEEE 34 node system with solar Photovoltaic (PV) in multiple locations is modeled in PSCAD/EMTDC. The TW, ML method's protection scheme is built upon an efficient signal-processing stage, using the Discrete Wavelet Transform, and scaled-down Random Forest models that classify the fault location into several protection zones. The analysis is focused on the quantification of the sensitivity and selectivity of the proposed protection scheme. Furthermore, estimations of the false trip probability and average unnecessary load loss are included, as these events may occur due to the misoperation and miscoordination of the proposed datadriven, signal-based relays. Results show high TW detection rates and fault location accuracies, which cause a small and bounded percentage of imprecise fault locations and unnecessary load loss. Similarly, the same IEEE 34 node system is modeled in OpenDSS and a custom OC protection scheme is designed. The comparison between both methods leads to the conclusion that TW, ML methods can be a significantly faster aid to traditional protection.