UPQC and DVR Systems

IUPQC Systems and VSCs

• In an IUPQC system, VSC-1 connects in shunt to feeder-1, while VSC-2 connects in series with feeder-2

DVR Control Strategies

• In-phase compensation results in the minimum injected voltage magnitude for DVRs

DVR Devices

• IGBT or IGCT is commonly used in DVRs for fast response

DVR Function

• The primary function of a Dynamic Voltage Restorer (DVR) is to compensate for voltage sags and swells

IUPQC Implementation

• The DC capacitor voltage remains stable when an IUPQC is implemented, as per experimental results

Unified Power Quality Conditioner (UPQC)

• A UPQC combines a DVR and a DSTATCOM

UPQC Converters

• The series-connected converter in a UPQC aims to control the magnitude of the load bus voltage

Load Bus Voltage Regulation

• A UPQC regulates the load bus voltage by injecting variable active voltage in phase with the source current

Shunt Converter objective

• The main control objective of the shunt-connected converter in UPQC is to regulate the DC bus voltage and balance the source currents

DSTATCOM Operation

• If the susceptance (B) of a DSTATCOM is increased while keeping voltage constant in a linear V-I characteristic system, reactive power (Q) increases proportionally with B

Distribution Network Control

• Vector Control is a typical control strategy for DSTATCOM operation in a distribution network

DSTATCOM Purpose

• The primary purpose of a DSTATCOM in a power distribution network is to compensate for reactive power

DSTATCOM Vector Diagrams

• The vector diagram of a DSTATCOM indicates Vi leads I when reactive power is supplied

DSTATCOM Components

• A DSTATCOM system includes a VSI, an AC filter, a DC energy storage device, and a coupling transformer

UPQC Context

• In the context of UPQC, PCC stands for Point of Common Coupling

Voltage Source Converters (VSCs)

• The primary function of Voltage Source Converters (VSCs) in an IUPQC system is to connect back to back through a common energy storage DC capacitor

IUPQC Aims

• IUPQC aims to solve harmonic elimination and swell mitigation in power distribution systems

Shunt Bi-directional Converter

• The shunt bi-directional converter performs all of the following in a IUPQC system:
  • Injects reactive current to compensate current harmonics
  • Provides reactive power to improve the power factor
  • Draws fundamental current and compensates for power loss

Improving Power Quality

• IUPQC improves power quality in two feeders by regulating bus voltage and load current

Gating Signals

• Sinusoidal Pulse Width Modulation (PWM) is the technology used in IUPQC for generating gating signals

Adaptive Controllers in FACTS

• Adaptive controllers must evolve to handle the increased variability and intermittency of power generation from renewable sources when integrating renewable energy sources into the grid

Adaptive Controller Risks

• A potential issue when implementing an adaptive controller in a FACTS device is the risk of instability due to rapid parameter changes

Adaptive Controller Role

• Adaptive controllers in FACTS dynamically adjust compensation based on load variations and system disturbances

Mitigating Oscillations

• Adaptive controllers in FACTS contribute to mitigating power system oscillations through continuous real-time adjustment of control parameters to dampen oscillations effectively

FACTS Online Algorithms

• Online learning algorithms in adaptive controllers for FACTS can improve control strategies in real-time by learning from the system's current state and performance

Dead-beat Controller Drawback

• A potential drawback of using a dead-beat controller in FACTS devices is that it may lead to overshoot or instability in the presence of model inaccuracies or unmodeled dynamics

Dead-beat Controller Advantages

• A key advantage of using a dead-beat controller in FACTS devices is that it provides quick response and precise control over the system parameters

FACTS Purpose

• The primary purpose of using FACTS (Flexible AC Transmission Systems) is to control power flow and improve the stability and efficiency of power transmission systems

Implementing Adaptive Controllers

• A key benefit of implementing adaptive controllers in FACTS is improved system stability and adaptability to varying network conditions

Damping Design

• The participation factor in a damping controller design indicates the contribution of a state variable to a particular oscillation mode

Modal Controllability Factor

• In damping control, the term 'modal controllability factor' signifies the effectiveness of a controller in influencing specific oscillation modes

Modulation Controllers (SMCs)

• The primary objective of tuning supplementary modulation controllers (SMCs) in power systems is to optimize damping across several critical swing modes.

Modulation Controllers (SMCs) Purpose

• The purpose of tuning supplementary modulation controllers (SMCs) in power systems is to damp critical swing modes and improve stability

Power Oscillation Damping

• The mechanical damping is considered in the generator models

TCSC Reactance

• Power Oscillation Damping (POD) is the essential component in a feedback control system to modulate the value of TCSC reactance

Swing Equation

• The stiffness matrix evaluated at the equilibrium point [K] represents in the swing equation

Power Swing Damping Controller

• The primary purpose of a Power Swing Damping Controller (PSDC) is to damp oscillations in power systems

Transformation Matrix Significance

• In the context of modal transformation of swing equations, the transformation matrix [Q] allows for the diagonalization of matrices [M] and [K]

Negative Phase Indicator

• The NPI (Negative Phase Indicator) index provides phase information on the eigenvalue shift due to the controller

Damping Controller Objectives

• The primary objective of designing damping controllers in power systems is to improve system stability by damping oscillations