Partial Discharge Detector Self-Powering Circuit
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Solution Overview
Problem
Existing circuit arrangements for voltage testing and partial discharge detection in medium or high-voltage systems often require auxiliary energy, leading to maintenance-intensive batteries and potential interference from external power supplies, which can result in incorrect signal interpretations.
Innovation Solution
A circuit arrangement that couples the partial discharge detector unit to the ground side of a system capacitor parallel to the capacitive coupling electrode, allowing energy extraction from the measurement signal for partial discharge detection and display, and remains inactive during periods without sufficient signal, thereby avoiding high-frequency interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If auxiliary power (battery or mains voltage connection) is used to power the partial discharge detector unit, then the detector can operate continuously, but maintenance-intensive batteries are required and interference signals may be generated that can be mistakenly interpreted as partial discharge signals
Solution Approach 1:
The partial discharge detector unit powers itself by drawing energy from the measurement signal it processes. The evaluation circuit extracts sufficient energy from the incoming measurement signal to operate the detector without requiring external auxiliary power sources, thereby eliminating battery maintenance and interference signals from external power supplies
Solution Approach 2:
An energy storage element (capacitor) acts as an intermediary between the measurement signal and the evaluation circuit. The capacitor accumulates energy from the measurement signal and supplies it to the evaluation circuit, enabling the detector to operate autonomously while filtering out high-frequency interference signals
2Measurement precision
If the partial discharge detector unit remains active during periods without measurement signals, then it can detect partial discharges immediately when signals appear, but it consumes energy continuously and may detect high-frequency interference signals as false partial discharge signals
Solution Approach 1:
The partial discharge detector unit operates periodically rather than continuously. The evaluation circuit remains inactive during periods without measurement signals and is activated only when energy is available from the capacitor, thereby reducing energy consumption while maintaining detection capability during active periods
Solution Approach 2:
The detector monitors the presence of measurement signals and adjusts its operational state accordingly. When a measurement signal is detected, the capacitor charges and the evaluation circuit activates; when no signal is present, the capacitor discharges and the circuit enters standby mode, creating a feedback-based active/inactive cycle
3Measurement precision
If the partial discharge detector circuit is coupled to the conductor signal input, then it can detect partial discharges, but it requires auxiliary power and cannot operate without external energy sources
Solution Approach 1:
The measurement signal serves multiple functions simultaneously: it provides the measurement data for partial discharge detection and also serves as the power source for the evaluation circuit. This multi-functionality eliminates the need for separate auxiliary power supplies and simplifies the overall device architecture
Solution Approach 2:
The power supply function and the measurement function are merged into a single system. The evaluation circuit is designed to extract and utilize energy from the measurement signal itself, combining what were previously separate functions (measurement and power supply) into one integrated operation
Data Source
Figure 1
AI summary
1. Circuit arrangement for voltage testing and partial discharge detection. 2.1. Circuit arrangement for voltage testing and partial discharge detection in a single- or multi-phase medium- or high-voltage system, with one or more conductor signal inputs (11, 12, 13), each of which is configured for coupling to a capacitive coupling electrode (21, 22, 23) connected to a conductor (L1, L2, L3) of the system, at least one voltage testing unit (3) coupled to the respective conductor signal input (11, 12, 13) and configured for threshold-based voltage state detection, and at least one partial discharge detector unit (4) configured for partial discharge detection with respect to the respective conductor (L1, L2, L3), comprising a partial discharge detector circuit (5) and a partial discharge indicator circuit (7) coupled thereto.and a power supply for the partial discharge detector unit (4) with a first power supply circuit (8) for supplying the partial discharge detector circuit (5) with energy from the respective conductor signal input (11, 12, 13) and/or with a second power supply circuit (9) for supplying the partial discharge indicator circuit (7) with energy from the respective conductor signal input (11, 12, 13). 2.2. According to the invention, an input side (5a) of the partial discharge detector circuit (5) can be coupled via a partial discharge connection path (37) to a grounding side (39) of a system capacitor (CS1, CS2, CS3) that is electrically parallel to the capacitive coupling electrode (21, 22, 23). 2.3. Use for voltage testing and partial discharge detection in single-phase or multi-phase medium- or high-voltage systems.