What is loop resistance and why should it be measured regularly?

In a substation, loop resistance refers to the total resistance encountered by current as it flows through a closed circuit or loop. This includes conductor resistance, contact resistance, and other impedance factors that affect the flow of current.The loop resistance in a substation mainly involves the following components:

Conductor resistance: The resistance of the conductor in the circuit, such as copper or aluminum wires.
Contact resistance: The resistance at joints, connection points, or switchgear. If the contacts are poor, the contact resistance can significantly increase.
Grounding resistance: The resistance between the equipment and the ground.
Measuring loop resistance helps ensure good electrical connections in the circuit, reducing power loss and preventing overheating. If the loop resistance is too high, it may result in decreased operational efficiency and even pose safety risks.

In a substation environment, measuring loop resistance is commonly used to assess the quality of electrical connections, especially at switchgear and busbar connections, to ensure low resistance and maintain the reliability of the power system.

JYL100B/200B has a maximum output current of up to 200A, with a measurement range of 0Ω to 100mΩ. It is lightweight and offers precise testing (±0.2μΩ), utilizing the Kelvin four-wire measurement method to effectively eliminate the influence of the test leads' resistance on the results. This instrument is suitable for measuring the contact resistance of circuit breakers, disconnectors, grounding switches, transformers, busbars, high-voltage switchgear, and grounding conductors. It features high output voltage and extended duration, allowing for continuous long-term measurement. Additionally, it can measure the primary resistance of current transformers and perform group measurements of grounding wires

JYL100B/200B Technical Features:

1.The Max. test current can reach 200A which can test Min.0.01μΩ contact resistance value

2.With high output voltage, the test line is easy to carry and connection

3.The test output current is from high accuracy switch type constant-current source, no manual adjustment required, which will shorten test time and improves test accuracy.

4.Adopts Kevin four-pole wiring method to eliminate the effect of test wire resistance to test results effectively.

5.The current compensation function is added, which effectively reduces the influence of the current shunt of the double-ended ground wire of the GIS switch on the test results.

6.With overheat protective circuit which can ensure the instrument is reliable and stable during long time continuous work

7.The instrument is simple in operation. With a light weight, it is suitable for outdoor work.

8. With RS485 communication interface for remote control measurement(with operation software) .

9. With U disk storage interface and built-in printer.

TECHNICAL PARAMETERS:

Figures on display	Four and half figure display
Type	100B		200B
Output current	50A	100A	50A	100A	200A
Test range	0~100mΩ	0~50mΩ	0~100mΩ	0~50mΩ	0~20mΩ
Accuracy	0.5% ± 0.2μΩ
Minimum resolution	0.01μΩ
Output voltage	DC 10V
Power supply in operation	AC220V±10%,50Hz
Temperature in operation	-20 ~40℃
Relative humidity	≤80%RH,  No dew
Volume	Length 360mm x Width 235mm x Height 270mm
Net weight	8.5 kg

JYL100B/200B Main Application Object Range: