Chia-Chi Chu

• PhD
• Professor (Full) at National Tsing Hua University

The recent advancements in distributed renewable energy resources pose challenges for dynamic simulations of comprehensive power system models. This paper introduces a distributed co-simulation framework aimed at enhancing the scalability and accelerating the simulation process of large-scale power systems. Initially, a distributed and decoupled mo...

Fault detection and failure mode diagnosis are of crucial importance in operation and maintenance (O&M) of photovoltaic (PV) power stations. In this work, advanced artificial intelligence techniques are exploited to optimize these O&M tasks for 150 PV power stations in Taiwan with total power rating around 54 MW. First, the response of each inverte...

A model-free data-driven Q-learning-based distributed control is proposed for achieving autonomous voltage restoration in isolated AC microgrids (MGs) subject to input saturation. First, by defining the control objective in terms of local neighborhood tracking errors, the voltage restoration problem can be solved by the distributed pinning-based co...

Unlike conventional model-based distributed control of the isolated AC microgrid (MG) in which the stability of the closed-loop system can not be guaranteed especially when the operation condition is deviated from its nominal value, by exploring real-time measurement data, a model-free reinforcement learning (RL) design for frequency synchronizatio...

With the rise of environmental awareness and carbon emissions concerns, many regions in the world have growing integrations of renewable energy sources (RES) and energy storage into both conventional transmission grids and distribution grids in the past two decades. Even though the grid resilience can be indeed improved in some aspects, power elect...

Due to the recent rapid developments in fast charging technology for electric vehicles (EVs), these flexible mobile storage resources can provide auxiliary services to the power grid in emergency circumstances. Therefore, it is imperative to develop a resilient enhancement planning scheme for this coupled network under severe contingencies. To this...

This paper delves into the blackout incident within Taiwan's power grid on March 3, 2022, commonly referred to as the 303 blackout. This outage led to a loss of power supply amounting to around 10.5 GW, roughly one-third of the daily electricity demand of Taiwan's entire power system. As a consequence, approximately 5.49 million households across T...

Decaying DC offset frequently emerges as a major issue in power systems, especially under fault conditions. This leads to a distortion in the current waveform associated with the fault, which could significantly challenge protective and control mechanisms, possibly leading to their malfunction or breakdown. These decaying DC components (DDCs) compl...

This paper introduces a novel control strategy for enhancing the performance of the three-phase Vienna rectifier when faced with grid voltage disturbances. Unlike conventional methods, which typically employ three control loops for current regulation, capacitor voltage balance, and output voltage control, the proposed approach integrates a fundamen...

The sparse communication network exposes the AC microgrid (MG) with higher risk under malicious cyber attacks. Intrusion detection of malicious cyber attacks becomes a critical issue in operations of isolated AC MGs. In this work, a general framework for detecting cyber intrusion deception attacks is proposed by using localized dual variables of th...

Since communication channels of microgrids (MGs) are prone to environmental noises, control signals used in distributed control architecture will be polluted. In this paper, these noises in communication channels are addressed in distributed control of MGs. A distributed noise-resilient fixed-time consensus-based secondary control of hybrid inverte...

Parallel connections of three-phase Vienna rectifiers are commonly used to increase the power ratings of electric vehicle charging stations in recent years. However, parallel operation can create a path for zero sequence circulating current (ZSCC), particularly when the rectifiers are operating under interleaved modes with unbalanced filter inducto...

With the increasing penetration level of renewable energy resources with less system inertia, accurate estimation of the power system inertia has become a critical issue for maintaining the frequency stability of the entire power system. To tackle out this challenging task, a two-stage data-driven method is proposed in this paper for estimating the...

This article proposes an active Islanding Detection Method (IDM) integrating Frequency Locked-Loop (FLL) for the detection of voltage phase and frequency at the point of common coupling (PCC) and a modified Auto Phase Shift (APS) method for three-phase Distributed Energy Resource (DER) serving a local RLC load. The FLL is composed of a double secon...

The illegal use of electricity, defective meters, and malfunctioning infrastructure is major cause of non‐technical losses (NTLs) in electric distribution systems. Although machine learning techniques have been widely studied to solve this problem, a new framework is proposed to address the following challenges. (i) Given that fraudulent consumers...

The high penetration of renewables has amplified errors in forecasts of wind and solar power generation that are made to support the operation of power systems. To guarantee the security and reliability of the power system, sufficient dispatchable power generation capacity must be reserved. Various studies of the use of risk assessment to improve o...

An accurate and prompt estimation of phase angles, frequency, and magnitudes of the grid voltage is extremely important in paving a good platform for a fast and reliable operation of power grid monitoring, protection, and control. The phase-locked loop (PLL) served this purpose for decades, while the concept of the frequency-locked loop (FLL) has b...

To restrict transient dynamics of each distributed generator (DG) in isolated AC micro-grids (MGs), an optimal distributed alternating direction method of multiplier (ADMM)- based control scheme, will be explored for achieving frequency synchronization within a given finite horizon. By introducing the consensus variable, we re-phrase the frequency...

This paper is concerned with frequency synchronization of heterogeneous second-order forced Kuramoto oscillator networks. Under this model, each second-order oscillator is driven by a periodic external force and its dynamics will be affected by the inertia and the damping coefficient. By introducing the second-order differential inequality, we firs...

A differential inequality approach is utilized to derive several stability conditions for synchronizing heterogeneous first-order forced coupled Kuramoto oscillator networks. First, we show that if either the amplitude of the external force is large enough or all natural frequencies equal to the external frequency, the heterogeneous first-order for...

Renewable sources of energy, including wind and solar power, can sustainably provide electricity for end-users. However, a high penetration of renewables presents operational challenges in the power system because the renewable power generation is uncertain and changes the net load profile to a "duck-curve". This paper investigates unit commitment...

Due to generation increase and load growing in recent years, Taiwan power system has faced with some transient instability problems. To tackle out this challenging task, two advanced techniques, including system integration protection scheme (SIPS) and automatic reclosing of transmission lines, are considered in Taiwan power system recently for tra...

Due to their salient features, modular multilevel converters (MMCs) are particularly suitable for a high voltage direct current (HVDC) transmission system. Nevertheless, for an HVDC system, each phase of the MMC terminal may consist of several hundreds of submodules (SMs). This imposes a particularly challenging in terms of steady-state simulation...

The displacement of synchronous generators by converter interfaced energy renewable resource essentially reduces the system inertia, which can trigger under-frequency load shedding relay. To support the frequency containment, virtual inertia control (VIC) and fast frequency control (FFC) based on energy storage system (ESS) have been developed. Mos...

Recently, Taiwanese government has announced an ambitious energy policy: up to 20 percent of total power will be generated from renewable energy resources by 2025. Under such high-level penetration level of renewable energy resources, the typical net load curve will be definitely reshaped as the so-called duck curve. Operation modes of pumped hydro...

The problem of phasor measurement units (PMUs) placement for state estimation in modern power grids has emerged with renewed interest in recent years. Conventional optimal PMU placement (OPP) formulations without limitations on observability propagations May pose the power grid at the higher risk of losing its observability under unexpected conting...

A consensus-based distributed voltage control architecture of isolated DC microgrids (MGs) with deception attack awareness is investigated in this paper. Firstly, a fully distributed voltage control algorithm with only adjacent information sharing is proposed by expanding the consensus-based distributed algorithm in AC MGs. To further enhance the a...

This study presents the effect of Taiwan's energy policy on its unit commitment in the year 2025. Taiwan's energy policy has been changing since 2005, since when it has required the decommissioning of nuclear power plants in response to the crisis in Fukushima, the adoption of the Kyoto Protocol, and the increase of renewable sources of power gener...

Traditionally, voltage stability assessment (VSA) are widely investigated by model-based approaches. Several achievements have been developed along this direction, including continuation power flow methods (CPFLOW), direct methods, and optimal power flow methods. Since precise model information are required and their computations are very demanding...

Voltage instability is a growing threat to the security and the reliability of power grids, especially as the penetration level of intermittent renewable energies increase significantly in recent years. Voltage instability and even voltage collapse will take place as the loss of control of the voltage profiles in a power system. To achieve more eff...

As the power system becomes more stressed and the penetration of intermittent renewable energies increase, voltage stability assessment (VSA) becomes a key concern for maintaining and enhancing the security of bulk power systems. Physically, the phenomenon of voltage instability is indeed caused by an uncontrollable drop in system voltage after bei...

The conventional step-down dc–dc converters under the single pulsewidth modulation (PWM) control scheme may not provide enough step-down voltage conversion capabilities with considering the minimum on -time and the switching frequency of the power switch. In order to overcome this difficulty, a dual PWM control scheme for designing the high step-...

The isolated power system in Kinmen island, Taiwan has already implemented the special protection system (SPS) to prevent various critical contingencies occurred during the past decade. However, when one severe N-2 contingency occurred on July 26, 2013, the SPS was not properly armed its under-frequency load shedding (UFLS). After re-examining tran...

When the power grid encounters unexpected contingencies, conventional optimal phasor measurement units (PMUs) placement formulations with unlimited observability propagations may increase the risk of losing the observability. In order to tackle out this difficulty, an enhanced optimal PMU placement (OPP) formulation with considering bounded observa...

The estimation of phase-angle, frequency, and amplitude are vital for the control of grid-connected power electronic systems in both single-phase and three-phase systems. The singlephase enhanced phase-locked loop (1P-EPLL) and two-phase enhanced phase-locked loop (2P-EPLL techniques can be used to estimate single-phase and three-phase grid voltage...

This paper presents an integrated scheme for supplementary damping control of UPFCs in order to mitigate low frequency oscillations in power systems. The entire control system consists of the primary control and the supplementary control. In the primary control, the passivity-based control (PBC) is considered in the current control loop of two conv...

Phase-locked loops (PLLs) are widely utilized for grid synchronization and control of power electronic converters. More recently, both in-loop filtered and pre-filtered based PLLs have become more popular due to their prompt and accurate estimations of grid voltage quantities. In the past, an advanced filter viz., multiple delayed signal cancellati...

The grid voltage information such as the phase-angle, the frequency, and the amplitude, is crucial for the design of synchronization and control of power converters in the micro-grid. The conventional approach to estimate the grid voltage information is accomplished by phase-locked loop (PLL) techniques. Among various existing PLL techniques, filte...

This paper presents a framework for distributed frequency control and intrusion detection in isolated microgrids (MGs). First, a distributed secondary control for isolated MGs, consisting of the local droop control at the primary level and a distributed node-to-node update at the secondary level, is proposed for achieving a proportional power shari...

The illegal use of electricity, defective meters, and a malfunctioning infrastructure are major causes of Non-Technical Losses (NTLs) in electric distribution systems. Although the use of supervised machine learning techniques to detect NTLs has been widely studied, further research is needed in order to address some significant challenges. (i) Giv...

Phase-locked loops (PLLs) are the most widely adopted techniques for synchronization of distributed generation units to the utility grid. However, when the grid voltage is polluted with severe unbalances and harmonics, the accuracy and performance of the conventional PLL will be deteriorated. This paper proposes a novel filtering technique, called...

Phase-locked loop (PLL) techniques are widely utilized for synchronization and control of grid-connected power electronic systems for estimation of phase-angle, frequency, and amplitude of the grid voltage. Recently, an advanced scheme, called the three-phase enhanced PLL (3P-EPLL), has been proposed for estimating the grid voltage information. How...

This paper investigates a probabilistic assessment of Available Transfer Capability (ATC) by Optimality Condition Decomposition (OCD) techniques and Latin Hypercube sampling (LHS) method in power systems with penetration of wind energy resources. First, the ATC assessment is mathematically formulated as a non-linear optimal power flow problem. Then...

In this paper, a novel load margin sensitivity method based on the proposed novel direct method have been studied with wind power generation systems. In the beginning, a bidirectional sweep approach is applied for power flow analysis when wind power generators are linked to the main power grid. Fixed-speed and doubly-fed induction generators are in...

A back-Electromotive-Force (EMF) model reference adaptive system (MRAS)-based sensorless control scheme is proposed for a grid-connected doubly-fed induction generator (DFIG). Based on the stator-side and the rotor-side dynamic models of the DFIG, both the reference model and the adaptive model of the proposed back-EMF-based DFIG are investigated....