Talk about the importance of arc light protection in medium and low voltage power systems

Acquaray Electric Co.
, Ltd.
Shanghai Jiading [Abstract]: Due to the lack of busbar protection, many outlets, frequent operation, the distance between the three-phase conductor lines and the distance from the earth, the susceptibility to small animal hazards, and the quality of equipment manufacturing is worse than that of high-voltage equipment, the susceptibility of arc accidents is much higher than that of high voltage
.
Based on this, this paper first explains the causes and hazards of arc light, then introduces the national standards for arc light protection devices, and finally introduces the principle of arc light protection and the composition
of the device.
【Keywords】:Medium and low voltage power system; Busbar protection; In recent years, arc light failure accidents in medium and low voltage power systems have occurred frequently, which not only affects the smooth operation of the power supply system, but also causes serious personal injury and property losses, and even spreads to the surrounding environment, resulting in a series of secondary disasters
.
Therefore, it is necessary to configure arc-light protection devices in medium and low voltage power systems
.
Second, the causes and hazards of arc light 1, the arc light failure accidents that occur in the operation of the medium and low voltage power system are mostly affected by environmental conditions, the insulation material is moisture, the surface of the equipment produces condensation and adhesion pollution, so that the equipment insulation level drops and causes accidents
.
After the normal maintenance of the equipment failure and the misoperation of the live equipment, the tool is missed in the switchgear and the wrong wiring and bus connection insulation aging and mechanical wear, overvoltage small animals, dust, temperature, humidity, corrosion and other environmental factors such as capacitive grounding current expansion Human misoperation often causes arc fault accidents
。 The artificial reasons generated by arc light mistakenly enter the live interval isolation switch misoperation forget to ground in the work area to forget to measure the high voltage in the work area 2, arc fault accident of the huge ring-breaking arc temperature up to 10,000 degrees Celsius, equivalent to 2 times the surface temperature of the sun, overheating will lead to busbar, cable melting, gasification, cable cladding overheating will lead to pressure rise, so that the switchgear explosion switchgear strong vibration, so that the fixed element loose high temperature burning skin, strong light stabbing the eye to produce a large number of harmful gases, Injuries respiratory system blast sound shock damage eardrums, visceral debris flying, causing bodily injury, and even death The degree of harm caused by arc light failure accidents depends on the arc light current and excision time, and the energy generated by the arc rises
rapidly in exponential law with I 2t.
When the total excision time is greater than 100ms, it will cause different degrees of damage to the equipment, so the shorter the total excision time, the better
.
Third, the relevant standards of arc protection NB/T 42076-2016 arc protection device selection guidelines This article explains the selection conditions
of arc protection devices.
GB/T 14598.
302-2016 Technical requirements for arc light protection devices This article describes the operating conditions
of arc light protection.
DL/T 1504-2016 General technical conditions for arc light protection devices This article explains the configuration principles
of arc light protection.
Fourth, ARB5 series arc protection principle and system composition arc light protection device through the arc light + current mutation of the double criterion or arc light single criterion to start the protection, the operation time of the arc single criterion action time ≤7ms; The arc light + current dual criterion time ≤ 20ms
.
ARB5 series arc protection device consists of ARB5-M main control unit, ARB5-E expansion unit, ARB5-S arc probe, arc optical fiber and pigtail fiber
.
V.
Conclusion The principle of arc light protection is simple, the structure is simple, the action is fast and reliable, which improves the concept of traditional bus protection and is of great significance in preventing arc light failure accidents, and can reduce equipment damage and casualties, and ensure the safe and reliable operation
of medium and low voltage switchgear 。 Reference[1] Accuray Enterprise Microgrid Design and Application Handbook[2].
NB/T 42076-2016 Guidelines for the selection of arc light protection devices[3].
GB/T 14598.
302-2016 Technical requirements for arc protection devices[4].
DL/T 1504-2016 General technical conditions for arc protection devices Author introduction: Ren Yunye, male, is currently working in Ankerui Electric Co.
, Ltd.
, the main research direction is relay protection and arc protection
of medium and low voltage power supply systems.