High Voltage Detection Circuit Noise Suppression

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Solution Overview

Problem

High voltage phasing voltmeters face inaccuracies due to interference from high frequency electromagnetic interference (EMI) and lack of noise suppression, leading to unreliable phase-to-phase voltage measurements in electrical power distribution systems.

Innovation Solution

A high voltage detection device with a probe connected in series to a resistor, featuring an input circuit with ferrite beads for noise suppression, a differential amplifier for signal conversion, a low pass filter, and a communication circuit for phase angle measurement, along with a battery-powered circuit for noise-free signal processing and display.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If high voltage detection is performed in close proximity to high voltage fields, then voltage measurements can be obtained, but measurement accuracy deteriorates due to electromagnetic interference

Engineering Contradiction:

Improvevoltage measurement accuracyVSAvoidelectromagnetic interference

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent introduces ferrite beads as intermediary components in the signal path between the probe and the measurement circuit. These ferrite beads act as magnetic shields that absorb and dissipate electromagnetic interference, preventing high frequency noise from coupling into the measurement circuit while allowing the desired voltage signal to pass through.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces mechanical shielding approaches with electromagnetic field-based solutions using ferrite materials. Instead of physical barriers, the system uses the magnetic properties of ferrite beads to create a magnetic shield that selectively attenuates electromagnetic interference in the high frequency range while maintaining signal integrity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If noise suppression circuits are added to eliminate electromagnetic interference, then measurement reliability improves, but device complexity increases

Engineering Contradiction:

Improvemeasurement reliabilityVSAvoidcircuit complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies noise suppression measures locally at critical points in the circuit rather than throughout the entire system. Ferrite beads are placed specifically at the probe input and around sensitive measurement circuits where electromagnetic interference coupling is most likely to occur, providing targeted protection without adding unnecessary complexity to other parts of the device.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the electrical parameters of existing circuit components to improve noise immunity. By selecting ferrite beads with specific impedance characteristics and placing them at strategic locations, the circuit's frequency response is modified to attenuate high frequency noise while passing the measurement signal, achieving noise suppression through parameter optimization rather than adding complex active filtering circuits.

Inventive Principle:

Principle #35Parameter changes

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 provides accurate, noise-free phase-to-phase voltage measurements and phase angle determination, effectively suppressing high frequency noise and ensuring reliable operation in high voltage environments.

Implementation Method 1

The input circuit is adapted to suppress high frequency noise pick up by the probe

Methodology Applied

Scientific EffectElectromagnetic absorption: Absorption (EM radiation)

Implementation Method 2

A voltage detection circuit comprises a differential amplifier circuit for converting the bipolar voltage to a proportionate voltage signal

Methodology Applied

Scientific EffectDifferential amplification:

Implementation Method 3

The circuit comprises a low pass filter circuit

Methodology Applied

Scientific EffectElectromagnetic filtering: Filter (electronic)

Data Source

PatentUS9086436B2Method of high voltage detection and accurate phase angle measurement in cordless phasing meters

Publication Date: 2015.07.21 HONEYWELL SAFETY PRODUCTS USA INC

AI summary

A high voltage detection device comprises a probe comprising an electrode for contacting a high voltage electrical line. The electrode is connected in series with a resistor. A meter comprises a housing enclosing an electrical circuit for measuring line voltage. The electrical circuit comprises an input circuit for connection to the probe. The input circuit is adapted to suppress high frequency noise pick up by the probe and develop a bipolar voltage representing measured line voltage. A voltage detection circuit comprises a differential amplifier circuit for converting the bipolar voltage to a proportionate voltage signal. A signal processing circuit receives the proportionate voltage signal and drives the display for displaying the measured line voltage.