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Leon Zhang sales consultant
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Email: zxl635973785@gmail.com
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Phone/WhatsApp: +86 13655813266
ASF-441H Anti-islanding protection products
Our self-developed ASF-441H Anti-Islanding Protection Device trips equipment under abnormal frequency/voltage, with multi-detection functions and standby unit startup to ensure grid stability.
Protection Functions (with ANSI Code)
51V/67, 81U, 27, 81O, 59, 32R, 78, 27
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Description
Overview of Anti-islanding protection
- The ASF-441H Anti-Islanding Protection Device is a new-generation protection device independently developed and manufactured by our company.
- It is designed to disconnect specified power equipment (such as transmission lines or unit transformers) when the system frequency or voltage drops, thereby ensuring the safe and stable operation of the power grid (including low-frequency/low-voltage disconnection, high-frequency/low-voltage disconnection, and rapid startup of standby units under low-frequency/low-voltage conditions).
- It features functions such as low-frequency detection, low-voltage detection, over-frequency detection, over-voltage detection, and reverse power detection.
Protection Functions (with ANSI Code)
- Three-stage compound voltage blocking directional overcurrent protection — ANSI 51V/67
- Three-round underfrequency protection: slip blocking and undervoltage blocking can be enabled or disabled; underfrequency load shedding output supports trip or alarm selection — ANSI 81U
- Three-round undervoltage load shedding function — ANSI 27
- Overfrequency protection: undervoltage blocking can be enabled or disabled; overfrequency load shedding output supports trip or alarm selection — ANSI 81O
- Overvoltage protection — ANSI 59
- Reverse power protection — ANSI 32R
- Reverse power recovery function
- Out-of-step splitting protection — ANSI 78
- Loss of voltage protection — ANSI 27
Anti-islanding Protection Principle
Setting Table
| No. | Description | Setting Range | Conversion Factor for Upload & Download |
|---|---|---|---|
| 1 | Control Word 1 | 0000～FFFF | ×1 |
| 2 | Control Word 2 | 0000～FFFF | ×1 |
| 3 | Control Word 3 | 0000～FFFF | ×1 |
| 4 | Low Frequency Start Delay | 0.1～120.00s | ×100 |
| 5 | Low Frequency Stage 1 Protection Delay | 0.1～120.00s | ×100 |
| 6 | Low Frequency Stage 2 Protection Delay | 0.1～120.00s | ×100 |
| 7 | Low Frequency Stage 3 Protection Delay | 0.1～120.00s | ×100 |
| 8 | Low Frequency Acceleration Delay | 0.1～120.00s | ×100 |
| 9 | Under-voltage Start Delay | 0.1～120.00s | ×100 |
| 10 | Under-voltage Stage 1 Protection Delay | 0.1～120.00s | ×100 |
| 11 | Under-voltage Stage 2 Protection Delay | 0.1～120.00s | ×100 |
| 12 | Under-voltage Stage 3 Protection Delay | 0.1～120.00s | ×100 |
| 13 | Under-voltage Acceleration Delay | 0.1～120.00s | ×100 |
| 14 | Overcurrent Stage 1 Delay | 0～120.00s | ×100 |
| 15 | Overcurrent Stage 2 Delay | 0～120.00s | ×100 |
| 16 | Overcurrent Stage 3 Delay | 0～120.00s | ×100 |
| 17 | Over-voltage Delay | 0.1～120.00s | ×100 |
| 18 | Over-frequency Delay (Stage 1) | 0.1～120.00s | ×100 |
| 19 | Reverse Power Delay | 0.1～120.00s | ×100 |
| 20 | Over-frequency Delay (Stage 2) | – | ×100 |
| 21 | Low Frequency Start Setting | 45.00～50.00Hz | ×100 |
| 22 | Low Frequency Stage 1 Protection Setting | 45.00～50.00Hz | ×100 |
| 23 | Low Frequency Stage 2 Protection Setting | 45.00～50.00Hz | ×100 |
| 24 | Low Frequency Stage 3 Protection Setting | 45.00～50.00Hz | ×100 |
| 25 | Frequency Change Rate 1 (Acceleration Setting) df/dt1 | 0.00Hz/s～20.00Hz/s | ×100 |
| 26 | Frequency Change Rate 2 (Blocking Setting) df/dt2 | 0.00Hz/s～20.00Hz/s | ×100 |
| 27 | Under-voltage Start Setting | 0.4～120.00V | ×100 |
| 28 | Under-voltage Stage 1 Protection Setting | 0.4～120.00V | ×100 |
| 29 | Under-voltage Stage 2 Protection Setting | 0.4～120.00V | ×100 |
| 30 | Under-voltage Stage 3 Protection Setting | 0.4～120.00V | ×100 |
| 31 | Under-voltage Blocking Setting | 0.4～120.00V | ×100 |
| 32 | Voltage Difference Abnormality Setting | 0.4～120.00V | ×100 |
| 33 | Loss-of-synchronism Voltage Setting | 0.4～120.00V | ×100 |
| 34 | Voltage Change Rate 1 (Acceleration Setting) dv/dt1 | 0.00V/s～200.00V/s | ×100 |
| 35 | Voltage Change Rate 2 (Blocking Setting) dv/dt2 | 0.00V/s～200.00V/s | ×100 |
| 36 | Overcurrent Stage 1 Setting | – | ×100 |
| 37 | Overcurrent Stage 2 Setting | – | ×100 |
| 38 | Overcurrent Stage 3 Setting | – | ×100 |
| 39 | Over-voltage Setting | – | ×100 |
| 40 | Over-frequency Setting (Stage 1) | – | ×100 |
| 41 | Reverse Power Setting | – | ×100 |
| 42 | Rated Current | – | ×100 |
| 43 | Negative Sequence Voltage Setting | – | ×100 |
| 44 | Under-voltage Setting | – | ×100 |
| 45 | Reverse Power Reset Setting | – | ×100 |
| 46 | Reverse Power Reset Time | – | ×100 |
| 47 | Over-frequency Setting (Stage 2) | – | ×100 |
| 48 | Oscillation Count | 0-20 | ×100 |
| 49~54 | Reserved | – | – |
| 55 | Voltage Loss Setting | 0.4～120.00V | – |
| 56 | Voltage Loss Delay | 0.1～120.00s | – |
| 57~64 | Reserved | – | – |
| 65 | CRC Check | – | – |
Outline and Installation Dimensions
FAQ
Q：What is the purpose of an anti-islanding relay?
A:Due to grid or natural factors, the local power system is likely to operate in island mode, posing risks to equipment and the grid. In solar power projects, the anti islanding protection solar inverter serves as the primary defense with inherent anti-islanding capabilities.
Though inverters (including the anti islanding protection solar inverter) and wind power systems have basic anti-islanding functions, installing an anti islanding protection relay at grid connection points provides reliable backup to enhance safety.
Note that anti virus protection installation long island is irrelevant to grid anti-islanding protection. When islanding occurs, the anti islanding protection relay and anti islanding protection solar inverter form a dual backup to quickly disconnect the islanded power source and eliminate risks.
Q：What is anti-islanding protection used for?
A：Disconnect distributed generation from isolated local grid to prevent out-of-supply safety risk.
Q：Detection modes equipped?
A：Both passive detection (U/f abnormal) and active disturbance detection are integrated.
Q：Typical applicable equipment?
A：Grid-connected PV inverter, small wind turbine and distributed cogeneration unit.
Q: What is anti-islanding protection?
A: It is a mandatory safety feature for grid-tied generators (solar/wind inverters). It detects unintended grid disconnection where local generators continue powering on-site loads to form an isolated “power island”, and immediately cuts off inverter output to eliminate safety and grid risks.
Q: What is an islanding condition?
A: Islanding is an abnormal state where the main grid trips, while local distributed generation keeps powering partial loads. The isolated area loses grid voltage and frequency constraints, leading to unstable power parameters.
Q: Why is anti-islanding protection necessary?
A: It avoids four key risks:
1) Safety risk: Energized isolated lines endanger maintenance personnel;
2) Equipment risk: Abnormal voltage/frequency damages on-site electrical devices and inverters;
3) Grid risk: Out-of-sync reconnection causes grid impact and equipment failure;
4) Compliance risk: Grid-tied systems are legally required to equip with qualified anti-islanding protection.
Q: What are the main anti-islanding detection methods?
A: Mainstream inverters adopt a dual combination of passive and active detection:
1) Passive detection: Real-time monitors grid voltage, frequency and phase. Triggers shutdown when parameters exceed standard thresholds (voltage ±10%, frequency ±0.5Hz). It causes no grid interference but has a minor non-detection zone (NDZ).
2) Active detection: Actively perturbs output frequency/voltage/phase (e.g. AFD). Normal grid suppresses deviations; grid disconnection leads to rapid parameter drift beyond thresholds. It achieves near-zero NDZ and high detection accuracy.
Q: What is the response time of anti-islanding protection?
A: Per global grid standards, inverters must shut down within2 seconds in most scenarios. Regional codes such as UK G98/G99 allow a maximum 5-second response to terminate islanding risks promptly.
Q: Which devices require anti-islanding protection?
A: All grid-tied distributed generation inverters, including residential/commercial PV inverters, micro-inverters, wind and energy storage grid-tied inverters. Off-grid-only inverters do not require this function.
Q: Does normal grid fluctuation trigger anti-islanding tripping?
A: No. Built-in voltage and frequency tolerance thresholds prevent misoperation under minor normal grid fluctuations. Protection only activates during complete grid outage or severe parameter deviation.
Q: Why do grid-tied solar systems stop working during blackouts?
A: This is the core anti-islanding mechanism: inverters shut down automatically during grid outages to avoid islanding. Only hybrid inverters with independent off-grid backup circuits can power critical loads in isolated off-grid mode without grid connection risks.
Q: What are the mainstream anti-islanding standards?
A: Key standards include IEC 62116 (PV anti-islanding test core standard), IEEE 1547 (distributed generation grid interconnection), UK G98/G99 and EU CE regulations. All grid-tied inverters must pass relevant anti-islanding tests for grid connection and market launch.
Q: What are the core anti-islanding test requirements?
A: Tests simulate the worst-case scenario where inverter output power matches local load power (highest NDZ risk). Devices must detect grid disconnection and shut down within specified time under all load and power conditions to pass certification.
Q: What are common anti-islanding faults?
A: Typical issues include:
1) False tripping (abnormal grid fluctuation, improper thresholds or parameter drift);
2) Detection failure (aging circuits or invalid parameters);
3) Protection failure caused by grid parameter sampling errors.
Q: How to resolve frequent anti-islanding tripping?
A: 1) Verify on-site grid stability to exclude grid anomalies;
2) Check inverter sampling circuits and wiring for looseness or poor contact;
3) Calibrate protection thresholds;
4) Upgrade firmware to optimize detection adaptability.
Q: Can anti-islanding protection be disabled manually?
A: Strictly prohibited. It is a mandatory safety and compliance feature. Manual disabling or parameter modification causes non-compliant grid connection, severe safety hazards and violation of grid operation specifications.
Q: How to maintain anti-islanding protection regularly?
A: 1) Inspect grid sampling wiring for firm connection and intact insulation;
2) Conduct annual anti-islanding function simulation tests;
3) Calibrate voltage/frequency detection parameters periodically;
4) Update firmware to keep optimal protection performance.
Q: What is Non-Detection Zone (NDZ)?
A: NDZ refers to the special condition where inverter output power closely matches local load power, making grid parameter deviation too slight for passive detection after grid disconnection. Modern active anti-islanding technology effectively eliminates NDZ for full-scene reliable detection.
Q: Do energy storage inverters have anti-islanding protection?
A: Yes. Grid-tied energy storage inverters integrate standard anti-islanding protection to cut grid-tied output during grid faults. Pure off-grid operating mode isolates from the grid via switches and will not trigger islanding protection.
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Professional Warranty: Reliable after-sales support for stable relay protection and long-term customer satisfaction.
xiao zhang –
This anti-islanding protection adopts combined passive & active detection algorithm to rapidly identify island operation of distributed generation. Fast response speed, flexible threshold configuration and multiple communication interfaces make it widely applied for photovoltaic and wind power grid-connected projects globally.
Jack –
Password protection prevents unauthorized setting changes — very secure.