Product Overview
The QKM3L series photovoltaic grid-connection special circuit breaker adopts a residual current operated circuit breaker (reclosing) as its main body, with enhanced PV-specific protection functions, dual-mode communication (HPLC or HPLC), and power quality monitoring & precise metering for power IoT applications. It is used to connect photovoltaic power generation systems to low-voltage grids, with the following core functions:
- Anti-islanding protection: When the grid is powered off, it provides islanding protection independent of the inverter itself, cutting off the connection between the PV system and the low-voltage distribution network.
- Overload & short-circuit protection: Whether it is a short circuit on the PV side or the grid side, the breaker trips to disconnect the grid connection, ensuring system stability.
- Power quality assessment: Performs harmonic analysis on grid voltage and current, providing data for power quality evaluation.
- Measurement function: Measures power, voltage, current, and frequency, supporting data analysis for regional power supply and load response.
This breaker complies with:
- GB/T 14048.2 Low-voltage switchgear and controlgear – Part 2: Circuit breakers
- Q/GDW 1972 Technical specifications for special circuit breakers for distributed photovoltaic grid connection
Model Selection Guide
| Code Segment | Definition | Options & Specifications |
|---|---|---|
| QKM3L | Product Code | Residual current operated circuit breaker for PV grid connection |
| 800 | Frame Grade (Inm) | 125, 250, 400, 630, 800 |
| C | Display Type | E: Digital typeC: LCD typeS: Standard type |
| M | Breaking Capacity | None: Low breakingM: High breakingS: Standard breaking |
| 3N | Pole Number | 3N (3P+N) |
| X | Type | None: StandardX: Premium |
| Z | Neutral Type | None: No neutralZ: With neutral |
| H | Communication Interface | None: RS485H: HPLC carrier module |
| 630A | Rated Current (In) | 125A: 50A–125A adjustable250A: 100A–250A adjustable400A: 160A–400A adjustable630A: 260A–630A adjustable800A: 320A–800A adjustable |
| R | Infrared Communication | None: No external communicationR: With infrared communication |
| T | Temperature Measurement | None: No temperature measurementT: Terminal temperature measurement |
| P | Topology Recognition | None: No topology recognitionP: Built-in topology recognition module |
| E | Data Processing | None: No encryptionE: Built-in EASM encryption chip |
| Y | Remote Control | None: Conventional external terminalY: Active remote controlW: Passive remote control |
| G | Application | G: PV grid connection |
Notes
- Switches with RS485 communication are basic models, and do not support temperature measurement, topology recognition, or data encryption.
- Switches with HPLC carrier modules are intelligent models, only supporting LCD display and neutral type (Z).
- For more functions and parameters, refer to the feature and technical specifications.
Functional Features Comparison
Legend: ● Default Function | ○ Optional Function
| Category | Function | Basic Model | Smart Model |
|---|---|---|---|
| Display | Indicator Light Display | ● | ● |
| Digital Tube Display | ● | ● | |
| LCD Display | ● | ● | |
| Metering Functions | Voltage & Current Monitoring | ● | ● |
| Power Quality Monitoring | ● | ● | |
| 0.5S Class Precision Metering | – | ● | |
| PV-Specific Protection | Overvoltage Delay Tripping | ● | ● |
| Undervoltage Instantaneous Tripping | ● | ● | |
| Undervoltage Delay Tripping | ● | ● | |
| Voltage-Hold Closing | ● | ● | |
| Anti-Islanding Protection | ● | ● | |
| Harmonic Monitoring & Protection | ● | ● | |
| Grid-Connected Power Quality Protection | ● | ● | |
| Live Grid-Connection Protection for PV Generation | ● | ● | |
| PV Generation Current Unbalance Monitoring & Protection | ● | ● | |
| Current Protection | Overload Delay Protection | ● | ● |
| Short-Circuit Delay Protection | ● | ● | |
| Short-Circuit Instantaneous Protection | ● | ● | |
| Residual Current Protection | Leakage Protection | ● | ● |
| Sudden Change Protection | ● | ● | |
| Auto-Ranging | ● | ● | |
| Special Breakpoint Protection | – | ○ | |
| External Tripping | Auxiliary Output Contact | ● | ● |
| Shunt Trip / Open Closing Contact | ● | ● | |
| Active Tariff Interface | – | ○ | |
| Optional Functions | Temperature Measurement | – | ○ |
| Topology Recognition | – | ○ | |
| Encryption Chip | – | ○ | |
| Communication Interface | RS485 Interface | ● | ● |
| HPLC Power Line Carrier | – | ● | |
| Low-Power Wireless Communication | – | ● | |
| Communication Protocol | Residual Current Operated Protector Communication Protocol | ● | ● |
| PV Low-Voltage Grid-Connection Switch Communication Protocol | – | ● |
Technical Specifications (English Professional Version)
| Item | Unit | QKM3L-125A | QKM3L-250A | QKM3L-400A | QKM3L-630A | QKM3L-800A |
|---|---|---|---|---|---|---|
| Model | – | QKM3L-125A | QKM3L-250A | QKM3L-400A | QKM3L-630A | QKM3L-800A |
| Frame Grade Rated Current (Inm) | A | 125 | 250 | 400 | 630 | 800 |
| Rated Current (Ie) | A | 0.4–1.0×Inm (continuously adjustable, step 1A) | Same as left | Same as left | Same as left | Same as left |
| Number of Poles | – | 3P+N | Same as left | Same as left | Same as left | Same as left |
| Rated Working Voltage (Ue) | V | AC400V, 50Hz | Same as left | Same as left | Same as left | Same as left |
| Rated Auxiliary Voltage (Us) | V | AC230V | Same as left | Same as left | Same as left | Same as left |
| Rated Insulation Voltage (Ui) | V | 1000 | 1000 | 1000 | 1000 | 1000 |
| Rated Impulse Withstand Voltage (Uimp) | kV | 8 | 8 | 8 | 8 | 8 |
| Arc Flash Distance | mm | ≤ 50 | ≤ 50 | ≤ 50 | ≤ 50 | ≤ 50 |
| Rated Ultimate Short-Circuit Breaking Capacity (Icu) | kA | 50 (No: 50; M: 65) | No: 50; M: 65; L: 20; S: 35 | No: 65; M: 85 | No: 65; M: 85; S: 35 | No: 65; M: 85; S: 35 |
| Rated Operational Short-Circuit Breaking Capacity (Ics) | kA | 35 (No: 35; M: 50) | No: 35; M: 50; L: 15; S: 35 | No: 45; M: 55 | No: 45; M: 55; S: 45 | No: 45; M: 65; S: 45 |
| Rated Short-Time Withstand Current (Icw) | kA/s | 1.25/1 | 3/0.5 | 5/0.5 | 8/0.5 | 10/1 |
| Residual Current Operating Characteristic | – | AC | AC | AC | AC | AC |
| Rated Residual Operating Current (IΔn) | mA | 30 (non-delay only), 50, 100, 200, 300, 400, 500, 600, 800, 1000 (stepped adjustable) | Same as left | Same as left | Same as left | Same as left |
| Limit Non-Drive Time (Δt) | s | 60ms / 100ms / 200ms | Same as left | Same as left | Same as left | Same as left |
| Auto-Reclosing Time | s | 20s–60s | Same as left | Same as left | Same as left | Same as left |
| Utilization Category | – | A | A | B | B | B |
| Operational Performance (Cycles) | ||||||
| Energized | Cycles | 1500 | 1000 | 1000 | 1000 | 500 |
| De-energized | Cycles | 8000 | 7000 | 4000 | 4000 | 2500 |
| Total Cycles | Cycles | 10000 | 8000 | 5000 | 5000 | 3000 |
| Overall Dimensions (mm) | ||||||
| Width | mm | 122/125 | 142 | 198 | 198 | 240 |
| Length | mm | 220/185 | 240 | 336 | 336 | 335 |
| Height | mm | 136.5/125 | 138/123 | 181 | 181 | 191 |
| Mounting Dimensions (mm) | ||||||
| W1 | mm | 60 | 70 | 96 | 96 | 116 |
| L1 | mm | 200 | 201 | 272 | 272 | 285 |