The causes and protection of relay protection interference in power systems are complex issues, involving multiple aspects such as electromagnetic compatibility, communication interference, and system faults. The following are some common causes of relay protection interference in power systems and their protective measures:

Transformer saturation: In power systems, current transformers are a very important device for measuring and controlling current. When the power grid operates normally, the operating error of the current transformer usually doubles the short-circuit current, affecting the sensitivity of the entire protection device and ultimately leading to the failure of the protection action. In order to avoid transformer saturation, some measures can be taken, such as reducing load, selecting transformer model and capacity reasonably, and strengthening relay protection operation management.

Incomplete relay protection work: Relay protection is an important link in ensuring the safe and stable operation of the power system. However, there are still some shortcomings in the current relay protection work of the power system, such as problems in the design, manufacturing, installation, and debugging of relay protection devices, which lead to incomplete relay protection work and cannot effectively eliminate the impact of equipment failures. In order to avoid incomplete relay protection work, it is necessary to strengthen the operation and management of relay protection devices, improve the technical level of relay protection personnel, and strengthen the maintenance and repair work of relay protection equipment.

Defect in fault handling technology of intelligent terminals: During the operation of relay protection in intelligent substations, if there is a fault defect in the intelligent terminal or merging unit terminal, it can also cause problems in the relay protection device, making it difficult to achieve safe and stable operation of the system. In order to solve this problem, it is necessary to strengthen the reasonable application of fault handling technology, analyze and study the causes of faults, and ensure that the relay protection device can function normally.

The measures to protect the power system from relay protection interference include: strengthening the protection against electromagnetic interference, adopting measures such as shielding, filtering, and grounding to reduce the impact of electromagnetic interference; Strengthen the protection against communication interference and take measures such as encryption, shielding, and filtering to reduce the impact of communication interference; Strengthen the protection against system faults, take measures such as system stability analysis and equipment selection to avoid the impact of system faults on relay protection devices.