In the power system, we often need to ensure the safe and reliable operation of equipment. And the DC resistance tester is one of the indispensable ‘doctors’. What is a DC resistance tester? Simply put, it is an instrument used to measure the DC resistance of electrical equipment such as transformers, switches, cables, etc. Why do we need to measure this resistance? Don’t underestimate it, this seemingly simple parameter can directly reflect the tightness of the internal connections of the device, whether the cross-sectional area of the conductor meets the standard, and whether there are potential issues such as virtual connections and oxidation.
Factors affecting DC resistance measurement
Temperature: The resistance value will change with temperature, so it is necessary to record and convert it to standard temperature during measurement, which is a very important step.
Contact resistance: The contact condition of equipment connection points and contacts directly affects the measurement results, and looseness or oxidation can cause an increase in resistance.
Measuring current: Different measured currents may cause slight differences, and choosing the appropriate current value is crucial to ensure measurement accuracy.
Clever use of DC resistance tester to make testing more efficient
To improve the measurement of DC resistance, mastering some tools and methods can achieve twice the result with half the effort.
Professional tool: The professional DC resistance tester provided by HV Hipot Electric Co., Ltd. usually has the characteristics of high precision, easy operation, and stable data. They can help us quickly obtain accurate measurement data and reduce human errors.
Data analysis: Combining historical data for comparative analysis can more effectively discover the aging trend or abnormal changes of equipment.
Standardized operation: Strictly following the operating procedures for measurement, ensuring a secure connection and suitable environment, is a prerequisite for obtaining reliable data.
The close connection between DC resistance tester and power equipment detection
The reason why DC resistance testing is important is because it is closely related to the safe operation of many power equipment.
Transformer: The DC resistance of the transformer winding is an important indicator for measuring its manufacturing quality and operating status. Abnormal resistance values may indicate problems such as winding turn to turn short circuits, loose joints, or broken wires.
Circuit breaker: The increase in contact resistance between the moving and stationary contacts of a circuit breaker will increase energy loss, cause severe heating, affect the breaking capacity, and even lead to contact burnout. The equipment of HV Hipot Electric Co., Ltd. has many applications in this area.
Cable: DC resistance measurement of cable joints and terminals can effectively detect defects such as poor connection and loose crimping.
How can we do better?
To maximize the effectiveness of DC resistance measurement, we can start from the following aspects:
Standardized operating procedures: Establish a unified and standardized measurement operation guide to ensure that all operators follow consistent standards.
Regular calibration of instruments: Ensure that the DC resistance tester itself is in good working condition, perform regular calibration to ensure measurement accuracy.
Correlation analysis: Combining DC resistance measurement data with data from other testing items (such as insulation resistance, dielectric loss, etc.) to form a more comprehensive equipment diagnostic report. HV Hipot Electric Co., Ltd. has provided excellent support in this regard.
On site experience accumulation: Relying on experienced technicians, they can more sensitively capture subtle anomalies in data through long-term on-site practice.
FAQ
Q1: What is the typical measurement current for a DC resistance tester? A1: This needs to be determined based on the resistance value of the tested device and relevant standards, usually ranging from a few milliamps to tens of amperes.
Q2: What is the impact of temperature on DC resistance measurement? A2: As the temperature rises, the resistance of the conductor will increase; As the temperature decreases, the resistance will decrease. So temperature correction is necessary.
Q3: What is the reason for the biased measurement of DC resistance? A3: Possible reasons include poor contact, insufficient cross-sectional area of the wire, broken conductor strands, oxidation corrosion, etc.
Q4: Apart from transformers and switches, what else can a DC resistance tester measure? A4: It can also be used to measure the DC resistance of various electrical equipment such as cables, busbars, and motor windings.
Q5: How to choose a suitable DC resistance tester? A5: Instruments that meet the requirements in terms of range, measurement accuracy, portability, etc. need to be selected based on factors such as the measurement object, accuracy requirements, and on-site environment.