The "Four Basic Principles" for one-time and complete elimination of electrical contacts (joints) overheating. The theories and concepts are applicable to various fields, industries, and units, from power generation, power supply to end-use power systems. In, any two current-carrying conductors (lines) are in contact with various types (a) electrical contacts. Such as split type, disassembly type, relative movable type electrical contacts (joints).

After more than ten years of practical tests in the "online operation" of some domestic power companies and power customers, and future history, it will prove: it is safe production of the power system, energy saving and consumption reduction, reliable power supply, social harmony, national economic development, and productivity improvement , And the revolution from "overheating" to "overheating" electrical contacts are instructive.

"Four basic principles" to eliminate the "overheating" of electrical contacts:

1. The "effective current-carrying cross-sectional area" of the electrical contact (joint) is the basis for the electrical contact's "overheating";

The so-called "effective current-carrying cross-sectional area" refers to the cross-sectional area that still has enough pressure to pass the rated current and short-circuit current under dynamic and thermal stability after energized operation. (Historical, traditional, and habitual so-called contact surface is not completely equal to "effective current-carrying cross-sectional area.")

2, the pressure of the electrical contact (joint) is the key to the "overheating" of the electrical contact;

In order to make the current flow through the electrical contacts more smoothly, the pressure of the "effective current-carrying cross-sectional area" in the contact surface is better than the pressure in any case. (The so-called "bus bar butt bolts should not be overtightened" in Article 11-055 Substation Maintenance Je54F3028 is incorrect, and academic discussion and debate can be held for this.)

3, the corrosion prevention of electrical contacts (joints) is very important;

We say that anti-corrosion is very important. It is by no means historical, traditional, or habitual to mistakenly believe that oxidation and corrosion are the cause or main contradiction of "overheating". (The last part has clarified and restored the true image of overheating of electrical contacts) It is just The "superficial phenomenon" we see after an overheating failure or accident is nothing more than. The so-called oxidation and corrosion refers to preventing the "effective current-carrying cross-sectional area" of the contact surface from being oxidized and corroded before research, design, manufacturing, installation, and power on. Otherwise, once the resistance of the electrical contact (joint) is greater than the resistance value of the conductor (line) of the same length (11-055LB1A4082 is not more than 20% is wrong!), perform a temperature measurement test of 1.5-2 times the rated current or a long time after power-on, The temperature of the electrical contact (joint) must be higher than the temperature of its conductor, which causes the electrical contact to overheat.

4, the metallic fatigue of the electrical contact (fastener) material must not be ignored;

This fourth basic principle is based on my continuous exploration, repeated testing, reverse thinking, and continuous improvement in decades of production practice. From the surface phenomenon of oxidation and corrosion, I further explore and analyze the causes of overheating of electrical contacts. At the end of the last century, we found the copper and aluminum metal fatigue that people had neglected for many years. It was the "main contradiction" of electrical contact overheating. It was the cause of overheating failures and accidents of various electrical contacts (joints). "The culprit"! Grasp the "main contradiction" and "four basic principles" at the same time, as long as there is enough "effective current-carrying cross-sectional area" in the pressure contact surface, and electrical contacts (joints) that are more than half of the cross-section of the conductor itself , The effective current-carrying cross-sectional area will not be oxidized or corroded. This is the theoretical basis for the long-term "overheating" of electrical contacts, and the essence of my independent innovation and completely independent intellectual property rights.

It is worth reminding: Except for the fourth basic principle, which has been overlooked in the past. History, tradition, and habit say that the contact surface will change after power-on operation. What we pursue is the cross-sectional area of ​​the electrical contact (connector) when passing the rated load current, including short-circuit current. For various types of electrical contact pressure (especially detachable electrical contacts, as long as it does not affect the subsequent disassembly, a higher pressure will only be beneficial). Under what circumstances, where the pressure is higher than the pressure is better. History, tradition, and habits believe that the effective current-carrying area of ​​the electrical contacts caused by oxidation and corrosion will not oxidize or corrode. The concept is just different.

Therefore, to correct the idea of ​​overheating of the original electrical contacts with the theory and concept of "not hot electrical contacts" is a revolution involving all fields and departments of the country, including the thoughts and concepts of every citizen who uses electricity. It won't be too much!

Sichuan Renyi Electric Co., Ltd.

Senior technician for substation maintenance: Ren Yi