1、 Background

With the rapid development of the power system towards intelligence and efficiency, distribution networks with voltage levels of 110kV and below, as well as internal power supply lines of industrial enterprises, have put forward higher requirements for the reliability, sensitivity, and integration of line protection devices as key links in power transmission. Traditional protection devices are gradually unable to meet the operational requirements of complex power grids in terms of response speed, anti-interference ability, and functional adaptability. There is an urgent need for a professional equipment that integrates precise protection and comprehensive measurement and control to ensure stable operation of power lines, quickly handle faults, and reduce power outage losses. In this context, Ankerui Electric Co., Ltd. has summarized years of product operation experience and developed the AM6-LD line fiber optic longitudinal differential protection measurement and control device based on actual user needs, filling the technical gap of the integration of conventional line protection and efficient measurement and control.

2、 Product Overview

The AM6-LD line fiber optic longitudinal differential protection and measurement device is a conventional line protection device designed specifically for voltage levels of 110kV and below, integrating protection and measurement functions. The device is based on fiber optic longitudinal differential protection and integrates 13 core protection functions, including complex voltage blocking overcurrent protection, zero sequence overcurrent protection, three-phase primary reclosing, low-frequency load shedding, and low-voltage load shedding. It also has comprehensive measurement and control capabilities such as manual contract period, telemetry, remote signaling, and remote control, which can quickly identify and accurately cut off line faults, as well as real-time monitoring and remote control of line operation status, providing full guarantee for the safe and stable operation of power lines.

3、 Product features and parameters

（1） Core Features

1. Quick and sensitive responseThe longitudinal differential protection criterion is efficient, with a total action time of less than 35ms, which can quickly handle line faults and minimize the impact of faults.

2. Outstanding anti-interference abilityAdopting comprehensive criteria such as "synchronous recognition" and "waveform recognition" to achieve CT saturation judgment, ensuring that the protection device always operates correctly during system faults, CT saturation, or fault transitions, effectively avoiding misjudgments.

3. Comprehensive and reliable information recordingIt can store 10 waveform files, 128 fault reports, and 4096 event records, with COMTRADE compatible fault waveform recording function, providing complete data support for accident analysis.

4. Strong operational adaptabilityEquipped with a 240 * 128 graphic LCD display, the interface is friendly and intuitive; Preset 16 sets of fixed values, supporting remote or local switching, adapted to different operational scenarios.

5. Wide communication compatibilitySupports international standard communication protocols such as DL/T667-1999 (IEC60870-5-103) and IEC61850. The communication medium can be twisted pair or fiber optic, and supports multiple timing methods such as B-code timing and SNTP.

6. Well designed hardwareAdopting an aluminum alloy fully enclosed chassis, with strict separation of strong and weak electricity, excellent heat dissipation performance, strong resistance to vibration and electromagnetic interference, and compliance with multiple industry standardized design specifications.

（2） Key parameters

1. Electrical parametersDC power input range 85V~265Vdc, static power consumption<10W, power consumption during operation<15W; rated input voltage supports 24V, 110V, 220V, and maximum output working voltage is 380V AC/250V DC.

2. protection performanceThe overcurrent and zero sequence overcurrent protection have a quick tripping action time of less than 35ms and a setting error of ≤± 2.5% or 0.02In; the low-frequency low-voltage load shedding and reclosing action delay accuracy is ± 20ms.

3. Measurement and Control PerformanceThe telemetry voltage/current accuracy reaches 0.2 level, and the power and electricity accuracy reaches 0.5 level; Supports up to 10 remote signals, 3 groups of 6 remote control relays, and the remote signal stabilization time can be set from 0 to 60000ms.

4. communication interfaceEquipped with multiple interfaces such as Ethernet (100Mbps), RS485, RS232, and fiber optic, the fiber optic transmission distance can reach up to 40km (1550nm wavelength), meeting the needs of different communication scenarios.

5. environmental adaptabilityWorking temperature range -40 ℃~+70 ℃, relative humidity ≤ 95% (daily average), altitude ≤ 1000m, seismic resistance up to horizontal acceleration of 0.30g and vertical acceleration of 0.15g.

（3） Size and dimensions

4、 Application scenarios

This device is suitable for various types of power line protection and measurement and control with voltage levels of 110kV and below. The core application scenarios include:

1. Urban and rural distribution network lines: ensuring rapid isolation of faults in the end lines of the distribution network and improving power supply reliability;

2. Internal power supply lines of industrial enterprises: adapted to high-voltage power supply lines of factories, mines and other enterprises to meet the stable protection needs of production electricity;

3. Conventional lines of intelligent substations: comply with the technical specifications for relay protection of intelligent substations and adapt to the IEC61850 engineering application model;

4. New energy supporting lines: providing precise protection and measurement for grid connected lines of distributed photovoltaic, wind power and other new energy projects;

5. Important load power supply lines: such as hospitals, data centers, and other places that require high continuity of power supply, to ensure uninterrupted operation of the lines.

5、 Summary

The AM6-LD line fiber optic longitudinal differential protection measurement and control device takes "precise protection+comprehensive measurement and control" as its core, integrating multiple advantages such as fast fault response, strong anti-interference ability, and flexible adaptability. It not only meets the safety protection requirements of 110kV and below voltage level lines, but also realizes real-time monitoring and remote control of line operation status. Its standardized design, extensive compatibility, and reliable performance not only align with the trend of intelligent development in power systems, but also effectively reduce line fault losses, improve operation and maintenance efficiency, and provide stable and efficient technical support for distribution networks, industrial enterprise power supply, and other scenarios. It is the preferred solution for power line protection and measurement and control.