Supercharge Your Innovation With Domain-Expert AI Agents!

Device and method for detecting a ground fault

By injecting a signal into the secondary winding of the voltage transformer and measuring the signal change at the neutral point, the problem of relying on third harmonics and high cost for detecting ground faults in the existing technology is solved, and 100% stator ground fault protection and low cost detection effect.

Active Publication Date: 2013-05-01
HITACHI ENERGY LTD
View PDF7 Cites 12 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Usually both current and voltage have to be measured, which leads to a costly solution

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Examples

Experimental program
Comparison scheme
Effect test

Embodiment Construction

[0029] In the example below, the invention is used to detect a stator ground fault of a generator and a voltage signal is injected into the secondary winding of a voltage transformer. However, the invention is not limited to injecting a voltage signal, and the motor may be, for example, a reactor.

[0030] figure 1 A circuit 1 comprising a three-phase generator 10 and a unit transformer 20 is shown. The generator also comprises a stator winding 12 having a neutral point 14 and a terminal 13 connected to the primary winding of the unit transformer. In this example, the primary windings of the unit transformers are delta connected to the terminals of the generator in order to isolate the generator from external faults of the network. However, it is also possible to star-connect the primary windings of the unit transformers.

[0031] The device 2 is configured to detect a ground fault of a stator winding and comprises a signal injection unit 20 , a voltage transformer 30 , a t...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

The present invention relates to an arrangement to detect a ground fault in an AC electric circuit (1) comprising an electric machine (10) having a neutral point (14) connecting to a neutral point and a terminal side (13), and a unit transformer (16) connected to the terminal side of the machine, wherein the arrangement comprises a signal injection unit (20), a voltage transformer (30) having a primary winding (31) connected to the terminal side (13) of the electric machine and a secondary winding (32) that is open delta-connected, an instrument transformer (40, 45) having a primary winding (48) connected to the neutral point (14) of the electric machine and a secondary winding (49), and a ground fault detecting unit (50). The signal injection unit (29) is configured to inject a signal to the secondary winding (32) of the voltage transformer (30). The instrument transformer (40, 45) is configured to measure the resultant injected signal at its secondary winding (49), and the ground fault detecting unit (50) is configured to detect a ground fault based on the measured signal.

Description

technical field [0001] The invention relates to the field of protection of electronic equipment such as generators, reactors or motors connected in AC power lines. It relates to devices and methods for detecting ground faults. It specifically concerns the detection of ground faults that may occur close to the neutral point of the motor. Background technique [0002] A ground fault in an electrical machine connected to the electrical network can pose a considerable risk to the correct operation of the electrical machine. For example, stator ground faults are the most common type of fault to which generators are subjected. It is the most frequent cause of damage to the stator windings of the generator, and it can be the immediate cause of subsequent phase-to-phase faults. The motor is grounded via a grounding system such as an impedance to limit mechanical stress and fault damage in the motor, to limit transient voltages during faults, and to provide means for detecting gro...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Applications(China)
IPC IPC(8): G01R27/16G01R27/18G01R31/02G01R31/06G01R31/34H02H5/10H02H11/00
CPCH02H3/17G01R31/025G01R31/34G01R31/52
Owner HITACHI ENERGY LTD
Features
  • R&D
  • Intellectual Property
  • Life Sciences
  • Materials
  • Tech Scout
Why Patsnap Eureka
  • Unparalleled Data Quality
  • Higher Quality Content
  • 60% Fewer Hallucinations
Social media
Patsnap Eureka Blog
Learn More

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic, Popular Technical Reports.

© 2025 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap|About US| Contact US: help@patsnap.com