What is Deployment Practice of Smart SPDs in PV Power Station Monitoring?

The deployment practice of smart surge protective devices (SPDs) in PV power station monitoring refers to the engineering solution of installing SPDs with online monitoring capability at the PV combiner box, DC side and AC side in a staged manner, enabling lightning event recording, leakage current detection, lifespan early warning and string-level data acquisition.

What is the core principle of Deployment Practice of Smart SPDs in PV Power Station Monitoring?

Based on IEC 61643 and GB/T 18802 standards, Type 1/Type 2 SPDs are deployed on the DC and AC sides of PV power stations respectively. Smart monitoring modules acquire SPD leakage, temperature, lightning count and other parameters in real time, uploading them via RS485/MODBUS to edge gateways and the cloud platform for SPD degradation trend analysis and lifespan prediction.

What scenarios does Deployment Practice of Smart SPDs in PV Power Station Monitoring apply to?

Suitable for centralized PV power stations, distributed rooftop PV, PV-storage integrated stations and other scenarios requiring lightning protection and string-level monitoring, covering combiner boxes, inverter front-ends, DC cabinets and AC distribution cabinets.

What are the engineering best practices for Deployment Practice of Smart SPDs in PV Power Station Monitoring?

Engineering deployment essentials include: selecting SPDs with matching voltage ratings for the DC and AC sides respectively, connecting SPD monitoring modules in combiner boxes to the RS485 bus, using string-level current acquisition for anti-reverse-flow and fault localization, configuring leakage current thresholds and lightning alarm rules on the host computer, and conducting periodic SPD condition inspections per GB/T 18802.

What are FEXLINK's capabilities in Deployment Practice of Smart SPDs in PV Power Station Monitoring?

FEXLINK provides the FSS Smart SPD, FS SPD Monitor, FG Smart Gateway and FEXLINK Cloud PV monitoring platform, supporting full-element SPD condition sensing, string-level data acquisition and anti-reverse-flow strategies. It has been deployed in projects including a 50MW PV power station in Northwest China.

Smart Surge Protector in Photovoltaic Power Station

1. Lightning Protection Requirements Analysis for PV Stations

PV stations are characterized by large footprint, exposed module arrays, long DC combiner circuits, and complex grounding systems, making lightning protection a key factor in determining their operational lifespan and power generation efficiency. According to GB 50057-2010 "Code for Design of Lightning Protection of Buildings" and IEC 61643-11 "Low-voltage SPDs - Part 11: SPDs connected to Low-Voltage power systems - Requirements," the DC side of PV stations should be equipped with T1+T2 SPDs, with continuous operating voltage Ucpv not less than 1.2 times the module open-circuit voltage Voc, and voltage protection level Up lower than the impulse withstand voltage Uw of the protected equipment. A 50MW PV station in Northwest China is located in a high-lightning area with over 40 thunderstorm days per year, with a 1000V DC system, 16A string current, and combiner boxes with 16 string inputs, placing clear demands on SPD intelligence, monitorability, and maintainability.

2. FSS Smart SPD Selection and Parameters

The FEXLINK FSS smart SPD is the flagship full-element SPD product, with 8 built-in sensor groups integrating acquisition, measurement, transmission, and intelligence. In this case, the selection parameters are: nominal discharge current In=20kA (8/20μS), maximum discharge current Imax=40kA, voltage protection level Up≤1.5kV, continuous operating voltage Ucpv=1000V DC, response time ≤25ns; configured with 4 temperature sensors (NTC type, 0-150°C accuracy ±1°C), 3 leakage current monitoring channels (range 0-2mA accuracy 10μA), 1 Lightning Strike counter (max 9999 times), and 1 voltage monitoring channel. The FSS supports dual OLED/digital tube display, with built-in fuzzy logic algorithm for degradation analysis and life prediction, and can upload 8 sensor data groups to the CW edge computing gateway via RS485/MODBUS-RTU. The product complies with four standards: IEC 61643-11, IEC 61643-21, GB/T 18802.1, and GB/T 18802.21.

3. Combiner Box Monitoring Deployment Solution

The 50MW station deployed a total of 320 combiner boxes, each configured with 2 FSS units (1 for DC positive and 1 for DC negative), 1 ESM smart lightning monitoring terminal, and 1 FR three-point grounding resistance monitoring module. The FSS uploads via dual 4-20mA analog and RS485 digital channels, ensuring local display even during communication interruptions; the ESM serves as a combiner box-level data aggregation node, collecting 16 string currents, voltages, and temperature data via CAN bus with a 100ms sampling cycle; the FR monitors combiner box grounding resistance in Real-Time with ±2% accuracy in the 10Ω-200Ω range, triggering local alarms when grounding resistance exceeds the design value (4Ω). All devices are aggregated via RS485 bus to one CW edge computing gateway shared by every 8 combiner boxes, with a total of 40 CW gateways deployed, uploading data to FEXLINK Cloud for big data analysis.

4. String-Level Data Acquisition and Anti-Backflow Strategy

Traditional PV station monitoring stops at the combiner box level, making string-level faults (single string mismatch, hot spots, PID degradation) difficult to detect early. In this case, FEXLINK deepened the monitoring granularity to the string level: 1 ESM is configured for every 16 strings, real-time acquiring four elements of string current (I), voltage (V), temperature (T), and status (S), with sampling accuracy of current class 0.5 and voltage class 0.2. The CW edge computing gateway has 60+ built-in edge AI algorithms that can identify typical faults such as string mismatch (>5% difference alarm), hot spot effect (>10°C temperature difference alarm), and PID degradation (<1MΩ·km insulation resistance alarm). For anti-backflow strategy, when the grid voltage falls below 198V or frequency deviation exceeds ±0.5Hz, the CW gateway triggers anti-islanding protection, cutting off the grid-connected switch via relay output with response time ≤100ms, complying with GB/T 19964 "Technical Requirements for Connecting PV Power Stations to Power Systems."

5. Lightning Strike Data and O&M Efficiency Analysis

Over 12 months of System Operation, 387 Lightning Strike events were recorded, including 5 strikes exceeding Imax (40kA) that triggered SPD action alarms; FSS leakage current monitoring detected 3 devices with leakage current exceeding the 1mA early warning threshold, which were confirmed degraded upon field inspection and replaced in advance, avoiding inverter damage from SPD failure; FR grounding resistance monitoring detected 2 grounding grid corrosion degradation points (rising from 2.1Ω to 6.8Ω), which were repaired in a timely manner, eliminating the risk of lightning strikes due to high resistance. After stable System Operation, O&M inspection efficiency improved by 60%, unplanned downtime due to lightning strikes decreased by 73% year-on-year, and the system recovered approximately 820,000 kWh of power generation losses over 12 months. At the local PV feed-in tariff of 0.35 yuan/kWh, the direct economic benefit was approximately 287,000 yuan, with an investment payback period of 11 months.

6. Industry Standards and Compliance Implementation

This case fully complies with the following standards: GB 50057-2010 "Code for Design of Lightning Protection of Buildings," GB/T 50064-2014 "Code for Design of Overvoltage Protection and Insulation Coordination for AC Electrical Installations," IEC 61643-11 "Low-voltage SPDs," IEC 61643-21 "SPDs connected to telecommunications and signalling networks," GB/T 18802.1 "Low-voltage SPDs - Part 1: SPDs connected to Low-Voltage power distribution systems," GB/T 19964 "Technical Requirements for Connecting PV Power Stations to Power Systems," and GB/T 50797 "Code for Design of PV Power Stations." FEXLINK's 408 national standard rules have been built into the CW edge computing gateway, which can automatically generate compliance reports after each Lightning Strike event, covering 15 key indicators including action value, action time, leakage current, and grounding resistance, for review by power regulatory authorities. The four products - FSS, ESM, FR, and CW - have all passed CE/CCC certification, validating the reliability and compliance of the full-stack solution across 200+ customer deployments.

Deployment Practice of Smart Surge Protector in PV Station Monitoring