Satellite time synchronization devices ensure precise, unified timing across power stations, enabling reliable protection, control, and monitoring in modern smart grids

The motor magnetic balance differential protection relay is an internal fault protection device used for medium- and high-voltage motors, detecting winding faults by comparing the current difference between the motor's input and neutral terminals.

Distance protection is a core protection method for high-voltage transmission lines, implemented using ​distance protection relays​ that determine fault location by measuring the impedance between the fault point and the protection installation point and executing tripping accordingly

A digital motor protection relay is an intelligent protection device that uses microprocessor technology to monitor and protect motors from various electrical faults.

Thermistor Motor Protection Relay​ monitors motor winding temperature in real-time using PTC/NTC thermistors, triggering protection (alarm or power cutoff) against overheating. It is suitable for critical equipment like servo and high-voltage motors, effectively preventing insulation damage and burnout failures.

Generator loss-of-excitation protection serves as a critical defense against generator excitation current failure caused by excitation system faults. As vital protection against system oscillations, terminal equipment damage, and reverse flow of reactive power during asynchronous operation.

Generator 100% stator earth fault protection overcomes traditional coverage limitations by combining two complementary methods. The third-harmonic voltage principle monitors the neutral-to-terminal voltage ratio to detect faults near the neutral, triggering when this ratio falls below a typical threshold of 0.3-0.5. Simultaneously, the low-frequency injection method introduces a 20Hz signal to measure insulation resistance across the entire winding, operating if resistance drops below pre-set thresholds (typically 1-5 kΩ). This dual approach ensures complete stator coverage without dead zones, provides high sensitivity for kΩ-range faults, and offers redundancy. Protection settings are derived from security margins applied to measured normal operating parameters, including harmonic voltage ratios and maximum unbalanced voltage, making it essential for large generator security.

Zero-sequence voltage protection is a vital protection scheme in power systems specifically designed for ground faults, particularly single-phase-to-ground faults. It is widely employed in systems with an ungrounded neutral, a neutral grounded via an arc-suppression coil (Petersen coil), or a low-resistance grounded neutral. The following provides a detailed explanation from three aspects: principle, function, and setting calculation.

Instantaneous Overcurrent Protection (IOCP) is a protection scheme used in power systems to rapidly clear short-circuit faults. Its defining feature is zero intentional time delay (or minimal delay), with typical operating times of 20–50 ms, complying with IEC 60255-151 (Overcurrent Protection Standards) and IEEE C37.91 (Guide for Protection Relay Applications).

Modbus, IEC 60870-5-103, IEC 60870-5-104, and IEC 61850 are widely used communication protocols in the fields of power systems and industrial automation. They exhibit significant differences in design objectives, architecture, data models, and application scenarios. Below is a detailed comparative analysis of them.