Impedance Injection Units for Sinusoidal Waveform Generation
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Solution Overview
Problem
Current impedance injection systems in high voltage transmission lines generate oscillations and harmonics due to large amplitude rectangular impedance waveforms, which can destabilize the power grid, and require a large number of impedance injection units (IIUs) to achieve sinusoidal waveform injection.
Innovation Solution
The system optimizes impedance injection by staggering and synchronizing the timing of rectangular waveforms from series-connected IIUs to generate a pseudo-sinusoidal waveform, reducing harmonic injection and oscillations, and uses a combination of standard synchronized and short pulses to minimize the number of IIUs required.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If large amplitude rectangular impedance waveforms are injected into the transmission line, then the impedance injection capability is improved, but oscillations and harmonics are generated that can destabilize the power grid
Solution Approach 1:
The patent segments the impedance injection process by dividing the rectangular waveform into multiple smaller rectangular pulses of different amplitudes and durations. These segmented pulses are injected in a staggered sequence to reconstruct the desired impedance profile while reducing the amplitude of any single injection event, thereby minimizing oscillations and harmonics.
Solution Approach 2:
The patent employs periodic action by injecting a series of periodic rectangular pulses with carefully selected frequencies and durations. The pulses are timed to cancel out harmful harmonics through destructive interference, while maintaining the effective impedance injection capability. The periodic nature allows for controlled harmonic cancellation.
2Manufacturing precision
If a large number of impedance injection units (IIUs) are used to achieve sinusoidal waveform injection, then the waveform quality is improved, but the system complexity and cost increase
Solution Approach 1:
The patent merges the functionality of multiple IIUs by coordinating the output of fewer units through sophisticated timing and amplitude control. By combining the injected pulses from a reduced number of IIUs in a staggered sequence, the system achieves sinusoidal waveform approximation equivalent to what would require many more independently operating units, thereby reducing system complexity.
Solution Approach 2:
The patent utilizes parameter changes by dynamically adjusting the amplitude, duration, and timing of rectangular pulses injected by each IIU. By varying these parameters across multiple injection events, the system synthesizes a sinusoidal waveform from rectangular components, achieving high waveform quality without requiring a large number of fixed-function IIUs.
3Ease of operation
If rectangular waveforms are injected to provide localized control, then the control capability is improved, but the injected impedance creates oscillations that interfere with control systems
Solution Approach 1:
The patent applies preliminary action by pre-calculating and pre-timing the sequence of rectangular pulses before injection. The control system determines the optimal injection schedule, amplitude, and duration for each pulse in advance, ensuring that the reconstructed sinusoidal waveform achieves the desired localized control effect without generating harmful oscillations that would interfere with control systems.
Data Source
AI summary
A method for synchronized injection of impedance into high voltage (HV) transmission line is disclosed. The method includes generating, by a plurality of impedance injection units (IIUs) coupled to the HV transmission line, impedance injection waves that cumulatively form a pseudo-sinusoidal wave. The method further includes optimizing, by the plurality of IIUs, the pseudo-sinusoidal wave to represent a pure sinusoidal wave. The method further includes injecting, by the plurality of IIUs, the pseudo-sinusoidal wave, as impedance, into the HV transmission line. The plurality of IIUs form multiple connection configurations in sequence, each connection configuration comprising one IIU or multiple IIUs in series, parallel or combination thereof, coupled to the HV transmission line.