In the fields of modern industrial automation and smart grid, a large number of sensitive electrical components are integrated in the electrical cabinet. However, the complex electromagnetic environment can easily cause mutual interference between components, resulting in signal distortion, equipment malfunction and other problems. Improving the electromagnetic compatibility of electrical components inside the electrical cabinet has become the key to ensuring the stable operation of the electrical system.
The electromagnetic compatibility problem in the electrical cabinet mainly stems from the generation and propagation of electromagnetic interference. When the internal components such as inverters and relays are working, they will generate high-frequency harmonics and pulse signals. These interference sources are transmitted through conduction, radiation and other means. At the same time, the external environment where the electrical cabinet is located, such as nearby high-power equipment and communication base stations, will also radiate electromagnetic interference into the cabinet. The electrical components themselves have insufficient anti-interference ability, and the layout and wiring are unreasonable, which further aggravates the impact of electromagnetic interference on the normal operation of the components.
Electromagnetic shielding is an effective means to isolate interference sources. The electrical cabinet can be wrapped with a metal shielding shell to form a complete shielding body to block the intrusion of external electromagnetic radiation. For sensitive components in the cabinet, such as control boards, signal processing modules, etc., metal shielding covers can also be equipped separately. At the same time, it is necessary to ensure that the shielding body is well grounded to avoid secondary interference caused by the floating potential of the shielding body. Conductive sealing strips, wire mesh, etc. are used in gaps, holes and other parts to ensure the integrity of the shielding and reduce electromagnetic leakage.
A reasonable grounding system can quickly discharge interference current and reduce the potential difference of electrical components. Separate the protective grounding, working grounding and shielding grounding in the electrical cabinet to avoid mutual interference. Use single-point grounding or multi-point grounding, and select according to the component characteristics and interference frequency. For example, single-point grounding is suitable for low-frequency interference, and multi-point grounding can better reduce the grounding impedance during high-frequency interference. In addition, ensure that the grounding conductor has sufficient cross-sectional area and good conductivity, and regularly check the reliability of the grounding connection to prevent the degradation of electromagnetic compatibility due to poor grounding.
Installing filters on the power and signal lines of the electrical cabinet can effectively suppress conducted interference. The power filter can filter out high-frequency harmonics and surge voltages in the power grid to ensure the quality of power supply; the signal filter can remove clutter during signal transmission and improve the purity of the signal. When selecting the filter, it is necessary to match it according to the operating frequency, current and voltage parameters of the line, and pay attention to the insertion loss and out-of-band suppression capability of the filter. In addition, installing the filter close to the interference source or the interfered component can enhance the filtering effect.
Reasonable component layout and wiring can reduce the coupling of electromagnetic interference. Separate the components that generate strong electromagnetic interference from the sensitive components and keep enough spacing. For signal lines, use shielded cables and follow the principle of "stay away from interference sources, shorten the routing length, and reduce the loop area" for wiring. Strong and weak current lines are laid separately to avoid parallel routing to prevent electromagnetic induction and capacitive coupling. At the same time, the cables are grouped and tied and fixed neatly to reduce the electromagnetic interference caused by line shaking.
To improve the electromagnetic compatibility of the electrical cabinet from the source, electrical components with high anti-interference ability can be selected. For example, using inverters, PLCs and other equipment with good electromagnetic compatibility performance, these components have considered anti-interference measures in the design stage and can better adapt to complex electromagnetic environments. In addition, selecting transformers and inductors with shielding layers and magnetic shielding functions, as well as wires and cables with good insulation performance, can also help reduce the interference generated by the components themselves and the influence of external interference.
After the electrical cabinet is assembled, a comprehensive electromagnetic compatibility test is required. Through conducted emission tests, radiated emission tests, electrostatic discharge immunity tests and other projects, the performance of electrical cabinets in different electromagnetic environments is tested. According to the test results, existing problems are analyzed and optimized, such as adjusting the shielding structure, improving the grounding method, replacing the filter, etc. Continuous testing and optimization can ensure that the electrical components inside the electrical cabinet achieve good electromagnetic compatibility and ensure the stable and reliable operation of the electrical system.
