美国光伏标准《组件级自我关断解决方案》分析

1、Module-level automatic shutdown solutions组件级自我关断解决方案The proposed 2017 NEC 690.12 may require a shutdown mechanism at module level to improve system safety 美国NEC2017 690.12建议光伏系统具备组件级别关断的能力，以提供最 好的系统安全性. 我们组件级关断的解决方案具有(1) Module-level automatic shutdown 组件级自动关断能力 (2) Module-level automatic shutdown s

2、olution can protect modules/junction boxes from irreversible damages caused by hotspot-induced over-heating and fire 阻止由于热斑或接线盒接线电阻过大带来的发热，导致组件和接线盒不可逆破坏 (3) Minimizes mismatch power losses caused by a temperature gap between cells, thanks to a unique junction box design and a patented radiation tech

3、nology 拥有专利的单向散热接线盒设计可以减少电池串温差带来的失配功率损失。 (4) integrated with junction box and no extral 集成到接线盒中，不需要其他设备Safety is always the top priority for any PV installationCurrent safety requirements in 2014 edition of NEC 690.12 2014 版美国国家电工规范690.12 规定The current code requires a 3-meter keep-out zone, commonly

4、 know as the “10-foot Rule” (see illustration), between all PV architectures and technologies; and a PV system should be able to reduce its voltages to less than 30v within 10 seconds美国国家电工规范 2014 版690.12 规定(1)所有光伏技术和系统都应该保持一个3米的空旷空间(2)这个光伏系统电压需要在10秒钟内下降到30V 以下Commonly used fast shutdown solutions i

5、n compliance with NEC 2014 690.12目前常用的符合版规范系统快速关断解决方案Right now, most residential PV systems use micro-inverters and AC modules, DC-to-DC converters, or string inverters:(1) Micro-inverters and AC modules: A loss of AC power immediately de-energizes all PV system circuits outside the array area(s); o

6、nly the inside of the circuits and external micro-inverters remain energized (关断交流开关后，将立刻导致光伏阵列外区域断电，只有微逆到组件的内部保持有电)(2) DC-to-DC converters: They can control voltage at the array, meeting the requirement for rapid shutdown; but they are only compliant with 2014 NEC 690.12 if they can meet the 10-sec

7、ond time limit, which is largely depending on inverter function ( DC-to-DC 优化器可以控制组件串电压，满足快速关断的要求。但只有满足10秒关断的条件才满足NEC 2014 690.12 的要求，这取决于组串逆变器的能力）(3) String inverter systems: To be compliant with 2014 NEC 690.12, an installation of a contactor combiner or a similar device is needed; such installati

8、on should be within 10 feet of the array, or within 5 feet of any buildings (组串逆变器至少需要配装一台带隔离器的汇流箱，并安装在离光伏阵列3米或建筑物1.5米范围内，使传统组串逆变器满足2014 版快速关断的要求）Main concerns for rapid shut-down solutions系统快速关断方案的主要问题The 2014 NEC Code added a rapid-shutdown requirement for PV systems on buildings with the goal of

9、allowing first responders to a quick and easy access to control PV system circuits; right now the most commonly used solution is to install a contactor combiner to disconnect DC power2014 版国家电工规范规定在所有建筑物上光伏系统要安装快速关断开关。目前大部分采用带隔离开关的汇流箱来满足这个快速断开光伏系统消除直流源的要求。Main concerns about current rapid shut-down

10、solutions (目前快速关断方案的主要问题)：(1) Though rooftop DC disconnection is important to the process of shutting down and isolating a PV array, it only stops the flow of current but does not provide isolation of voltage, which is typically greater than 300 Vdc and could be as high as 1,000 Vdc (目前的快速隔离方案只是关断了系

11、统的电流，但并没有将系统最高到1000Vdc的电压隔离出来）(2) In fire and other emergency situations, the standard procedure for first responders is to manually disconnect AC circuit breaker and manually open disconnection combiner circuits to initiate rapid shutdown; an automatic devise will be more desirable (在危险如火灾这样的情况时，标准

12、流程是我们只能等救火队员在现场手动 开一个AC或二个开关才能开启快速关断光伏系统功能,而不是自动关断）Proposed revisions in 2017 NEC 690.12 美国国家电工规范2017 建议版690.12 提高安全性The 2017 NEC proposes a reduction to a one-foot keep-out zone from the current ten-foot; this will lead to a major change in the way PV systems are designed and built In addition, a n

13、ew requirement for 80V or lower within the one-foot boundary will create the need for a module-level shutdown solution美国国家电工规范 2017 版690.12 建议(1)系统具有组件级的关断能力，使所有光伏系统周边安全区域从3米 减少到30厘米。这个变化将会影响到所有新建光伏电站的设计和建设Module-level automatic shutdown solution key advantages从系统手动快速关断方案到组件级自动关断的优势A brand new conce

14、pt plus a patented junction box and module design, MLASS can disconnect modules from the string with zero power output in emergency situations全新专利接线盒和组件设计，可以自动判别高温火灾情况，使组件输出开路，将组件从系统中断开。1.The safest way to de-activate a solar system without any DC input 组件零电压开路方案是保证光伏系统最安全的解决方案：Automatically initiat

15、e module-level shutdown; no need to disconnect AC breaker or combiner through manual switching （可以自动启动组件级关断功能，不需要救火专业人员手动关断交流或汇流箱中断路器）：Zero voltage/power output after module shutdown， No fire or other safety hazards inside the array area （组件开路后，组件输出电压/功率为零。发生火灾时，即使在光伏阵列中也没有危 险） 2.Requires no power f

16、or the solution, hence, a higher reliability （控制部分不需要电源供电,可靠性高）3.Prevents damages to module safety and reliability caused by hotpots and/or heat from improper connection inside junction box (发生热斑或接线盒连接不好时，接线盒内部升温。我们方案可以制止这种集热现象恶化，使组件可靠性和安全性提高。）4.Minimizes mismatch power losses caused by a temperatur

17、e gap between modules, thanks to a unique junction box design and a patented radiation technology （拥有专利的单向散热接线盒设计可以减少电池串温差带来的失配功率损失。MLASS vs. current electronic shutdown solutions 我们组件级关断方案和目前电子关断的比较The proposed 2017 NEC revision which sets an 80V limit would mean that additional module-level power

18、electronics would have to be used to reduce the voltages to this level. However, the best way to improve the reliability of a system, and thereby reduce installer service visits, is to reduce the number of components in it. 2017 NEC 修改版中关于80伏电压的限制，使利用电子方案实现组件级关断功能(比如DC-DC 优化器等)的厂商，需要添加新的电力元件来达到降低电压的

19、目的。然而,大量使用元件数量将导致系统的可靠性降低，成本提高。Modulelevel automatic shutdownDC-DC converter/micro-inverter shutdownModule output voltage/power is zero higher safety 组件关断后输出电压为零。比目前电子方案更安全Retains low voltage/power output lower safety 从组件串切断后，组件还有电压功率输出Automatic shutdown 可以自动关断组件Manual switching of AC Breaker & DC combiner需手动开