Resonant Grounded Distribution Fault Location Using Triplen Harmonics
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In active compensation resonant grounded power distribution systems, locating high impedance ground faults is challenging due to the cancellation of ground fault currents by arc suppression coils and inverters, making traditional fault indicator equipment ineffective, and thus, manual fault location processes are time-consuming and labor-intensive.
Innovation Solution
An array of line sensors is deployed along the power distribution circuit to detect specific harmonic signals intentionally allowed to pass through the system during a ground fault, enabling the pinpointing of fault locations by distinguishing between sensors that detect and those that do not detect these signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If active compensation is used to reduce ground fault current, then current magnitude is reduced to less than 5.0 Amperes, but fault location detection becomes ineffective
Solution Approach 1:
The patent introduces harmonic signals (specifically triplen harmonics at 3rd, 9th, 15th frequencies) as intermediary carriers to transmit fault location information. These harmonic signals serve as mediators that can pass through the active compensation system without being cancelled, allowing fault indicators to detect and locate faults even when fundamental frequency current is suppressed to less than 5.0 Amperes.
Solution Approach 2:
The patent changes the frequency parameter of the fault current from fundamental frequency to harmonic frequencies (3rd, 9th, 15th). By injecting harmonic signals into the system and allowing them to pass through the active compensation system, the fault detection mechanism transitions from detecting fundamental frequency current to detecting harmonic frequency signals, thereby resolving the detection ineffectiveness caused by current reduction.
2Ease of operation
If traditional fault indicator equipment is used, then fault detection is straightforward, but it becomes ineffective when ground fault currents are cancelled by arc suppression coils and inverters
Solution Approach 1:
The patent modifies the detection parameter from fundamental frequency current to harmonic frequency signals (3rd, 9th, 15th harmonics). Fault indicator equipment is configured to detect these specific harmonic frequencies that are intentionally allowed to pass through the active compensation system, maintaining detection simplicity while ensuring reliability in compensated systems.
Solution Approach 2:
Harmonic signals act as intermediaries that carry fault location information through the active compensation system. The fault indicators detect these harmonic mediators to determine fault locations, preserving the ease of operation of traditional indicators while ensuring they remain effective in the presence of arc suppression coils and inverters.
3Device complexity
If manual fault location processes are used, then no additional equipment is needed, but the process becomes time-consuming and labor-intensive
Solution Approach 1:
The patent uses harmonic signals as intermediaries that automatically carry fault location information to distributed fault indicators along the power line. This eliminates the need for manual inspection while keeping equipment deployment relatively simple, as fault indicators are passively deployed and automatically detect harmonic signals to pinpoint fault locations.
Solution Approach 2:
The system enables self-service fault location by automatically injecting harmonic signals and having distributed indicators detect and report fault locations without human intervention. This reduces both time and labor requirements while maintaining reasonable equipment complexity.
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
This approach allows for rapid and accurate localization of ground faults, reducing the time and effort required to identify fault locations, enabling quicker restoration of power and minimizing damage from high impedance ground faults.
Implementation Method 1
The Peterson coil and related equipment are calibrated or tuned to be equal to the leakage capacitance of the electrical conductors supplied by the substation transformer, thereby establishing a resonant circuit at the fundamental frequency.
Implementation Method 2
Power electronics and computer systems are installed at the same substation to measure the ground fault current.
Implementation Method 3
These systems use power inverters connected to a secondary or tertiary winding of the arc suppression coil to inject an equal and opposite current to eliminate the remaining 10% of the ground fault current
Data Source
AI summary
Disclosed are various embodiments for fault location in an active compensation resonant grounded power distribution system. In one embodiment, an inverter is programmed to allow a configurable set of triplen harmonics to pass during the ground fault condition for a duration of time. First current sensor data from a first line sensor mounted on a line conductor is analyzed to determine that a programmable set of harmonic currents are present. Second current sensor data from a second line sensor mounted on the line conductor is analyzed to determine that the programmable set of harmonic currents are absent. The second line sensor is downstream of the first line sensor on the line conductor. A ground fault being compensated for by the active compensation resonant grounded power distribution system is determined to be present on the line conductor between the first line sensor and the second line sensor.