In the context of busbar protection, the first two phases—busbar protection I and II—primarily focused on conventional busbar protection. In this article, we introduce a new type of busbar protection: arc protection. This system is specifically designed for medium and low voltage busbars, such as 35kV, 10kV, and 6kV systems.
Arc protection is a relatively new development that has emerged with advancements in optoelectronic technology. Unlike traditional protection schemes that rely mainly on electrical quantities like voltage, current, impedance, and power, arc protection uses both current and light intensity as its main criteria. The key feature of arc protection is its ability to detect the light emitted during an arc fault, which significantly improves the sensitivity and speed of fault detection compared to conventional methods.
Globally, many countries have recognized the importance of protecting medium and low voltage busbars. For instance, regulations in Europe, North America, Russia, and other Commonwealth countries require the installation of specialized busbar protection for these systems, with over 95% of medium-voltage switchgear being equipped with such protection. However, in China, dedicated fast busbar protection is not commonly installed for medium and low voltage systems. Despite this, the national standard "Design Rules for Relay Protection and Automatic Devices for Electrical Installations" (GB50062-92) and current industry guidelines are still met.
To address the lack of dedicated protection, three common methods are used:
1. Transformer backup overcurrent protection with typical action times ranging from 1.2s to 2.0s.
2. Transformer backup overcurrent protection combined with feeder quick-break protection and blocking, with action times between 0.3s and 0.5s.
3. Busbar differential protection similar to that used in high-voltage systems, with action times as fast as 15ms.
However, these methods are not ideal due to their long response times, which can lead to significant equipment damage before the fault is cleared. The severity of arc faults depends on the intensity of the arc current and the duration of the fault. The energy generated by the arc increases exponentially with time, making it crucial to minimize the cutting time.
According to foreign data, the impact of different arcing times on equipment is as follows:
| Arcing Time | Equipment Damage |
|-------------|------------------|
| 35 ms | No significant damage, usually can be reused after insulation testing |
| 100 ms | Minor damage, cleaning or minor repairs needed before reoperation |
| 500 ms | Severe damage, personnel may be injured; some equipment may need replacement |
The third method, busbar differential protection, is effective but limited by CT placement, complex wiring, and high costs, making it suitable only for critical substations.
With the increasing frequency of short-circuit faults in medium and low voltage systems, the need for specialized busbar protection is becoming more urgent. Arc protection addresses these shortcomings by detecting arc faults quickly and accurately.
Currently, there are several manufacturers producing arc protection systems, both domestically and internationally. Among them, VAMP is a well-known foreign brand, while domestic companies like Nanjing Hongyi Electric and Guodian Nanrui also offer competitive solutions.
Taking the DCR360ARC series from Nanjing Hongyi Electric as an example, the arc protection system operates based on a current acquisition unit, capable of correlating up to 272 arc sensors with any set of current signals. When an arc occurs, the arc sensor detects the light and sends a signal to the main control unit, triggering the protection mechanism.
The system includes both sudden and steady-state current starting components, using logical OR to determine whether to act. It can also use arc signal alone as the criterion for action.
The arc sensors are designed to distinguish between arc light and other light sources, ensuring accurate detection and reducing false trips. They use optical fibers to transmit signals to the main control unit, where photoelectric conversion takes place.
The arc protection system offers two types of output relays: electromagnetic and solid-state. Electromagnetic relays have a response time of no more than 8ms, while solid-state relays respond in less than 4ms, making them much faster than traditional protection systems.
The DPR362ARC model provides 100% fast protection for medium and low voltage busbars, cable compartments, and switchgear rooms. It is selective, meaning it can isolate only the affected area without impacting other parts of the system.
A typical application involves a system with two power lines, two main transformers, and two busbars connected in a single-bus configuration. The arc protection system includes a main control unit, current acquisition modules, and multiple arc sensors distributed across the switchgear.
In operation, if a fault occurs on one busbar, the corresponding arc sensors trigger the protection, isolating only the affected section while allowing the rest of the system to continue operating.
Overall, arc protection represents a significant advancement in busbar protection, offering faster, more reliable, and more selective fault detection, especially for medium and low voltage systems.
| About PEW Enameled Aluminium Wire |
We product class 155 enameled aluminium wire from 2.65-6.0 mm.
According to the characteristics of motor, transformer, automotive electrical and high-speed winding machine, we have advantages in resilience, breakdown voltages and have imported machine to protect the quality of Enameled Copper Wire.
|
Name |
Enameled Aluminum Wire |
|
Conductor |
Aluminum |
|
Dimension |
Diameter(mm): 2.65 ~ 6.0 |
|
Thermal Class(℃) |
130(Class B); 155(Class F); 180(Class H); 200(Class C); 220(Class C+); |
|
Standard |
IEC; ISO9000; ISO9001; IATF16949 |
|
Packing |
PT4 – PT200 or ply-wood spool |
|
Application |
Transformer; motor; generator; modern instrument; welding machine and so on. |
Class 155 heavy insulation thickness of modified polyester enameled aluminum round wire
Wire Of Motor,Pew Enameled Aluminium Wire,Aluminum Wire For Coils,Enameled Clad Aluminum Wire
HENAN HUAYANG ELECTRICAL TECHNOLOGY GROUP CO.,LTD , https://www.huaonwire.com