Controller Ripple Profile Optimization for HVDC Thermal Stress
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Solution Overview
Problem
Power transmission networks, particularly High Voltage Direct Current (HVDC) networks, face challenges in mitigating thermal and electric stress caused by ripple effects due to the switching behavior of power electronic network elements, which can lead to hotspots and adverse effects on the transmission lines.
Innovation Solution
A controller is configured to vary control parameters such as switching frequency and apparent impedance of power electronic network elements periodically or in response to temperature thresholds, optimizing the ripple profile along the transmission line to reduce thermal and electric stress. This involves simulating and selecting candidate configurations that minimize hotspot formation and stress, with a focus on conductor heating dominating dielectric heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If power electronic network elements are used to control power transmission, then power transmission efficiency is improved, but thermal and electric stress due to ripple increases
Solution Approach 1:
The controller varies control parameters periodically to change the ripple profile along the transmission line. This periodic variation redistributes thermal stress over time, preventing continuous concentrated heating at hotspot locations and allowing heat dissipation during lower-stress periods.
Solution Approach 2:
The controller changes control parameters (such as switching frequency or apparent impedance) to modify the ripple profile characteristics. By adjusting these parameters, the system optimizes power transmission efficiency while controlling the distribution and magnitude of thermal and electric stress on the transmission line.
2Temperature
If control parameters are varied to optimize ripple profile, then thermal stress is reduced, but system complexity increases
Solution Approach 1:
The controller uses feedback from temperature sensors or thermal models to detect hotspot conditions and adjusts control parameters accordingly. This feedback mechanism enables automatic optimization of the ripple profile to reduce thermal stress without requiring complex manual intervention or overly sophisticated control algorithms.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively mitigates hotspots and reduces thermal and electric stress along the transmission line by optimizing ripple profiles, ensuring more uniform heating and extending the lifespan of transmission lines while maintaining efficient power transmission.
Implementation Method 1
The switching behaviour of such network elements may result in a standing-wave signal along the power transmission lines of the network which is referred to as ripple (i.e. current ripple and/or voltage ripple)
Implementation Method 2
mitigate thermal and/or electric stress due to ripple in a transmission line of the network
Implementation Method 3
thermal and/or electric stress due to ripple in a transmission line of the network
Data Source
AI summary
There is disclosed a controller (112) for a power electronic network element (110) of a power transmission network (100), wherein the controller (112) is configured to vary a control parameter of the network element (110) which at least partly determines a ripple profile in a transmission line of the network. The controller (112) is configured to vary the control parameter between at least a first value and second value to cause the ripple profile in the transmission line to change; and the controller is configured to vary the control parameter periodically or in response to a signal indicating a threshold temperature at a hotspot location along the transmission line. A method of optimising control parameters for a power transmission network (100) is also disclosed.