Power Compensating Circuit for Weak Grid Frequency Stabilization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In weak electrical grids, load rejections due to faults can cause frequency increases, leading to generator trips and consumer downtimes, and the connection of harmonic filters can result in voltage overswings, further exacerbating the issue by reducing active and reactive power loading, making restarts time-consuming and costly.
Innovation Solution
A method and system that detect reduced power demand in the grid, calculate active and reactive power, and use a power compensating circuit with semiconductor switches to generate and adjust active and reactive power, stabilizing voltage and frequency by connecting and disconnecting a resistive load in sync with the grid frequency, thereby preventing generator trips and consumer downtimes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If load rejection occurs due to grid fault or large consumer failure, then frequency increases in the electrical grid, but this leads to generator trips and consumer downtimes
Solution Approach 1:
The controller detects reduced power demand before frequency instability occurs and activates the power compensating circuit in advance. By calculating the required active and reactive power compensation and connecting the resistive load through semiconductor switches, the system preemptively balances power demand, preventing frequency increases and generator trips before they happen.
Solution Approach 2:
The power compensating circuit with resistive load acts as an intermediary between the electrical grid and the power imbalance caused by load rejection. The semiconductor switches control the connection of this intermediate load to absorb excess power, stabilizing frequency and preventing the harmful effects from reaching generators and consumers.
2Reliability
If harmonic filters are connected for reactive power compensation, then reactive power is compensated, but this causes voltage overswing due to reduced active and reactive power loading
Solution Approach 1:
When harmonic filters are connected and reactive power compensation begins, the controller simultaneously activates the power compensating circuit to provide active power compensation. This preliminary anti-action counteracts the reduced active power loading that would otherwise cause voltage overswing, balancing the power demand before voltage instability occurs.
Solution Approach 2:
The system changes the operational parameters by dynamically controlling the resistive load through semiconductor switches. By adjusting the connection and disconnection of the resistive load based on detected power demand changes, the system modifies the active power consumption parameter to match the reduced loading conditions, preventing voltage overswing while maintaining reactive power compensation.
3Reliability
If power generators trip due to frequency increase, then generator protection is achieved, but restart of the overall system is time-consuming and costly
Solution Approach 1:
The controller detects reduced power demand and activates the power compensating circuit before frequency instability causes generator trips. By preemptively balancing active and reactive power through the controlled resistive load, the system prevents frequency increases that would trigger generator protection mechanisms, avoiding the need for time-consuming restarts entirely.
4Power
If a resistive load is connected to compensate power demand, then active power is generated, but device complexity increases with semiconductor switches and control circuitry
Solution Approach 1:
The power compensating circuit with semiconductor switches and resistive load serves multiple functions: it compensates active power demand, stabilizes frequency, prevents voltage overswing, and protects generators. This multi-functional design consolidates several protection and stabilization mechanisms into a single integrated system, managing complexity while providing comprehensive grid stabilization.
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 balances reduced power demand, stabilizes voltage and frequency, and prevents overswings, reducing the likelihood of generator and consumer trips, thus minimizing downtime and production losses in electrical grids.
Implementation Method 1
compensating at least a part of the active power and at least a part of the reactive power by controlling a power compensating circuit connected to the electrical grid... the at least resistive load may provide a resistance and optionally a capacity and/or impedance. An active power and a reactive power may be generated by connecting and disconnecting the at least resistive load to the electrical grid. This may be done with the frequency of the electrical grid.
Data Source
AI summary
A method for stabilizing electrical power in an electrical grid including: detecting a reduced power demand in the electrical grid; determining an active power and a reactive power to be compensated in the electrical grid; and compensating at least a part of the active power and at least a part of the reactive power by controlling a power compensating circuit connected to the electrical grid. The power compensating circuit including an at least resistive load connectable to the electrical grid via semiconductor switches. A compensated active power and a compensated reactive power is adjusted by setting switching angles of the semiconductor switches with respect to a phase angle of a grid voltage in the electrical grid.