CN209979775U

CN209979775U - Structure for judging fault point position

Info

Publication number: CN209979775U
Application number: CN201920509208.4U
Authority: CN
Inventors: 张彬; 朱兴文
Original assignee: Huaneng Shandong Shidaobay Nuclear Power Co Ltd
Current assignee: Huaneng Shandong Shidaobay Nuclear Power Co Ltd
Priority date: 2019-04-16
Filing date: 2019-04-16
Publication date: 2020-01-21
Anticipated expiration: 2029-04-16

Abstract

A structure for judging fault point position, including generating line N row, be provided with N row inherent ground point and unknown ground point on the generating line N row respectively, have and pass through line connection between N row inherent ground point and the unknown ground point, form return circuit one and return circuit two on the generating line N row, be provided with the ground resistance tester on return circuit one and the return circuit two. The utility model discloses can be according to the characteristic that just can record resistance under the condition that pincerlike ground resistance tester must have two point ground connections, confirm a ground point except the fault point earlier, utilize the position that pincerlike ground resistance tester confirmed the fault point again.

Description

Structure for judging fault point position

Technical Field

The utility model relates to an electrical technology field, in particular to a structure for judging fault point position.

Background

The traditional searching method for N-row grounding is to separate a load N line from N rows, separately measure the insulation of the separated N line and determine whether the N line has a grounding phenomenon. The method is suitable for the condition that a single cable or a small number of cables are available, but the number of two sections of emergency buses in a plant is as large as 400 load N lines, and each N line is connected with the N rows through bolts, so that the disassembly and the connection are troublesome, therefore, the problem of multipoint grounding of the N rows of emergency buses is solved, if the method is used for searching, the time and the labor are wasted, and the efficiency is extremely low.

Disclosure of Invention

In order to overcome the deficiencies of the prior art, the utility model aims to provide a structure for judging fault point position can just can record the characteristic of resistance according to the condition that pincerlike ground resistance tester must have two point ground connection, confirms a ground point except fault point earlier, utilizes the position that pincerlike ground resistance tester confirms fault point again.

In order to realize the purpose, the utility model discloses a technical scheme is:

the structure for judging the position of a fault point comprises N rows of buses 3, wherein N rows of intrinsic grounding points 1 and unknown grounding points 2 are respectively arranged on the N rows of buses 3, the two grounding points of the N rows of intrinsic grounding points 1 and the unknown grounding points 2 are connected through a ground wire, a non-fault loop (4) and a fault loop (5) are formed on the N rows of buses 3, and a grounding resistance tester 6 is arranged on the non-fault loop (4) and the fault loop (5).

At least one of said unknown ground points 2.

The non-fault loop 4 can not form a loop through a ground network, and the fault loop 5 can form a loop through the ground network.

The grounding resistance tester 6 is a clamp-on grounding resistance tester, and the clamp-on grounding resistance tester applies voltage to the loop through an exciting coil.

The test method for judging the position of a fault point comprises the following steps;

the method comprises the following steps:

determining an auxiliary grounding point except a fault point on the N rows 3 of the bus;

step two:

measuring the upstream and downstream resistances of the copper bar or the cable at the auxiliary grounding point by using a pincer-shaped grounding resistance tester;

step three:

if the measured resistance value is smaller, the fault point is positioned at the downstream of the direction from the auxiliary grounding point to the measuring point of the clamp meter;

if the measured resistance value exceeds the range of the clamp meter, indicating that no grounding fault exists at the downstream in the direction from the auxiliary grounding point to the measuring point of the clamp meter;

step four:

and (4) taking a point from the auxiliary grounding point to the fault point for testing, and when the resistance value of one point of two adjacent test points is smaller and the resistance value of the other point exceeds the range, indicating that the fault point is between the two test points, thereby determining the position of the fault point.

In the first step, the auxiliary grounding point is an inherent grounding point of the system or a grounding point manufactured by a person;

in the third step, if more branches have longer distance span, a method of firstly measuring 1/2 total number of the branch lines to be tested in the bus N rows and then measuring each branch line can be used.

The grounding point is selected from the beginning or the end of the N rows.

The utility model has the advantages that:

the clamp-on grounding resistance tester can only detect the resistance value of a grounding loop, if the tested grounding does not meet the loop condition, the tested branch does not form a loop, and the grounding resistance tester can obtain a result exceeding the upper limit (the tester displays 'OL' or '1500 omega'); if the tested ground meets the loop condition, that is, the tested branch forms a loop, the ground resistance tester will obtain a resistance value (the tester displays about 0.1 omega). In a one-point grounding system, an unknown ground fault point becomes a boundary point of whether or not a ground circuit is formed: namely, a grounding loop is formed between an unknown grounding fault point and a known system inherent grounding point, and a resistance value of about 0.1 omega can be measured; the branches except the unknown grounding fault point cannot form a grounding loop with the inherent grounding point of the system because of no grounding, and the resistance value of 'OL' or 'more than 1500 omega' exceeding the upper limit of measurement is obtained;

the characteristic that a grounding resistance tester is specially used for detecting the resistance value of the grounding loop is used for detecting and determining the grounding fault point of the loop. The method is convenient to operate, and the grounding resistance value can be read from the liquid crystal screen only by winding the jaw of the clamp meter around the grounding wire to be tested; the measurement is accurate, the grounding resistance tester has the main characteristic that the attached test ring is measured before the test, and if the reading is accurate, the grounding resistance value measured later is accurate; the accurate grounding resistance value can be obtained by only one operation of opening and closing the jaw without redundant operations such as wire disconnection and the like and without the limitation of the surrounding environment. The problem that the reliability of cable termination is influenced due to the fact that the disassembly and the connection are not standard is avoided.

Drawings

Fig. 1 is a schematic structural diagram of the present invention.

Fig. 2 is a schematic view of the work flow of the present invention.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

As shown in fig. 1:

the structure for judging the position of a fault point comprises N rows of buses 3, wherein N rows of intrinsic grounding points 1 and unknown grounding points 2 are respectively arranged on the N rows of buses 3, the N rows of intrinsic grounding points 1 and the unknown grounding points 2 are connected through lines, a non-fault loop (4) and a fault loop (5) are formed on the N rows of buses 3, and a grounding resistance tester 6 is arranged on the non-fault loop (4) and the fault loop (5).

As shown in fig. 2:

the method comprises the following steps:

step two:

step three:

if the measured resistance value is small (the metallic grounding is usually a few ohms to a few tens of ohms as in the 5-loop 2 test case in the figure), the fault point is positioned at the downstream of the direction from the auxiliary grounding point to the measuring point of the clamp meter;

if the measured resistance value exceeds the range of the clamp meter (as the test condition of 4-loop 2 in the attached figure), the downstream in the direction from the auxiliary grounding point to the measuring point of the clamp meter has no grounding fault;

step four:

The grounding point is selected from the beginning or the end of the N rows.

Example one:

the two emergency power supplies are connected through N lines, equipment powered by the two emergency power supplies is used on site, and the N lines of the two emergency power supplies are in short circuit in the cabinet, so that the whole N rows of the two emergency systems are in direct short circuit. Through on-site inspection, three electric control cabinets have the faults, which are respectively as follows:

1. an electric control cabinet 0SAC40GH001 of an air conditioning unit of an equipment protection room of an electric plant 7.5 m;

2. an electric control cabinet 0SAC10GH001 of an air conditioning unit of a 0 m A-row safe distribution room of an electric plant;

3. an electric control cabinet 0SAC11GH001 of an air conditioning unit of a 0 m B-row safe power distribution room of an electric plant.

Example two: the nuclear island conventional island N lines are connected, the nuclear island emergency bus and the conventional island working bus respectively provide a main power supply and a standby power supply for the conventional island electric door power distribution cabinet, and the two power supply N lines are connected at the N rows.

Example three: the puncture cable is pressed when the street lamp base is installed on the double-fence lighting circuit, so that the circuit has a metal continuous grounding fault.

The above experiments are internal experiments and are not disclosed.

Claims

1. The structure for judging the position of a fault point is characterized by comprising N rows of buses (3), wherein N rows of intrinsic grounding points (1) and unknown grounding points (2) are respectively arranged on the N rows of buses (3), the two grounding points of the N rows of intrinsic grounding points (1) and the unknown grounding points (2) are connected through a ground wire, a non-fault loop (4) and a fault loop (5) are formed on the N rows of buses (3), and a grounding resistance tester (6) is arranged on the non-fault loop (4) and the fault loop (5).

2. The arrangement for determining the location of a fault point according to claim 1, characterized in that the unknown ground point (2) is at least one.

3. The structure for determining the location of a fault point according to claim 1, characterized in that the non-faulty loop (4) is a loop that cannot be formed through the earth mat and the faulty loop (5) is a loop that can be formed through the earth mat.

4. The structure for judging the location of a fault point according to claim 1, characterized in that the ground resistance tester (6) is a clamp-on ground resistance tester, which applies a voltage to the circuit through an excitation coil.