[Paper Review] A Novel Hybrid Islanding Detection Method for Inverter-based DG

Maziar Isapour Chehardeh, Ehsan M. Siavashi|arXiv (Cornell University)|Feb 20, 2018

Islanding Detection in Power Systems11 references3 citations

TL;DR

This paper proposes a novel hybrid islanding detection method for inverter-based distributed generation (DG) that combines passive harmonic detection using an extended Kalman filter with active methods based on voltage rate-of-change and power shifting. The approach reduces detection time, minimizes the non-detection zone, and enhances reliability and security under varying power conditions, as validated in Simulink simulations across multiple system events.

ABSTRACT

A novel method for achieving a better performance using the combination of the available passive and active methods has been proposed. The algorithm detects the islanding in proper time by using harmonic detection, the average rate of change of voltage and shifting power generation. Harmonic detection in this method decreases process time and also differentiates between islanding and other power systems events. For harmonic detection, extended Kalman filter has been used. Besides, the reliability of the method increases using the average rate of change of the voltage. The proposed method uses a strategy for decreasing the non-detection zone. In this strategy, minimum and maximum average rates of change of voltage limits are defined to improve the security of the system. Therefore, three main specifications of a proper method, reliability, security and time of process are achievable by the combination of these passive and active methods. By applying different power system events under different power conditions, the proposed method has been verified in Simulink software.

Motivation & Objective

• To address the limitations of conventional passive and active islanding detection methods in terms of detection speed, non-detection zone, and reliability.
• To reduce the non-detection zone in islanding detection by introducing dynamic thresholds for voltage rate-of-change.
• To improve system security and detection accuracy by integrating harmonic detection with active control strategies.
• To achieve a balance between reliability, security, and fast detection time in inverter-based DG systems.

Proposed method

• Harmonic detection is performed using an extended Kalman filter to estimate harmonic components in the point of common coupling voltage.
• The average rate of change of voltage is calculated to detect abnormal system behavior indicative of islanding.
• Minimum and maximum thresholds for the average rate of change of voltage are defined to enhance system security and reduce false tripping.
• Power generation is intentionally shifted during detection to create measurable disturbances that distinguish islanding from normal events.
• The hybrid approach combines passive (harmonic-based) and active (voltage rate-of-change and power shifting) techniques to improve overall performance.
• A decision logic combines outputs from all three components to determine islanding status in real time.

Experimental results

Research questions

• RQ1 How can the non-detection zone in islanding detection be minimized using adaptive voltage rate-of-change thresholds?
• RQ2 To what extent does harmonic detection via extended Kalman filter improve detection speed and accuracy compared to conventional methods?
• RQ3 Can the integration of passive and active methods reduce false tripping while maintaining fast response times?
• RQ4 How does the proposed method perform under diverse power system events and varying load conditions?
• RQ5 What is the impact of power generation shifting on the reliability and security of islanding detection?

Key findings

• The proposed method significantly reduces detection time by leveraging real-time harmonic estimation through the extended Kalman filter.
• The use of defined minimum and maximum voltage rate-of-change limits effectively reduces the non-detection zone and enhances system security.
• The hybrid approach successfully differentiates islanding from other power system disturbances, such as load changes or faults.
• Simulation results in Simulink confirm reliable detection across multiple system events and varying power conditions.
• The method achieves a favorable balance between detection speed, reliability, and security, outperforming standalone passive or active methods.