The exact extract asks for active safety features of the Huawei smart string energy storage system. The correct answer is B, C, D. Full-lifecycle health protection is a safety-related function because it tracks the condition of the battery system throughout operation and helps detect deterioration or abnormal risks before they become failures. Real-time cell temperature monitoring is also an active safety feature because temperature is one of the most important indicators of battery abnormality and possible thermal runaway. Real-time cell-level voltage monitoring is similarly safety-critical because overvoltage, undervoltage, imbalance, or abnormal voltage behavior can indicate cell-level faults. Option A, SOC calibration, is important for energy management, usable capacity, and O & M efficiency, but it is not the best answer for “active safety features” in this list. Huawei ESS materials describe active protection through real-time cell detection, early warning, and rapid shutdown, while Huawei LUNA residential ESS material describes real-time cell-level temperature and voltage detection as active protection. References: Huawei Smart String ESS safety material; Huawei LUNA ESS active protection material.

The exact extract asks how long water spraying should continue after an energy storage equipment fire has been extinguished to ensure the temperature drops below 65°C. The correct answer is C. ≥ 2 hours. The reason is that lithium battery fires can reignite after visible flames are extinguished because residual internal heat and damaged cells can continue generating heat. Huawei’s ESS emergency-handling guidance states that a lithium battery fire may last for several hours and that, after the open flame is extinguished, water spraying should continue to cool the batteries. The guidance also requires monitoring until the battery temperature is reduced and stable before removal or follow-up handling. In the exam extract, the specified operational threshold is below 65°C, and the required cooling duration is at least two hours. Options B and D are too short for post-fire cooling, while option A is longer than the stated exam requirement. References: Huawei LUNA2000-S1 ESS emergency-handling guidance.

The exact extract states that the synchronous adjustment camera increases reactive power output when grid voltage rises and absorbs reactive power when grid voltage drops. That operating logic is reversed, so the correct answer is False. A synchronous condenser, or synchronous compensator, is indeed a synchronous machine without a mechanical driven load and is used for voltage and reactive power support. However, when grid voltage drops, the system should supply or generate reactive power to support voltage recovery. When grid voltage rises, it should absorb reactive power to prevent overvoltage and stabilize the system. The statement in the question says the opposite: it claims reactive power output increases when voltage rises and is absorbed when voltage drops. That contradicts normal reactive-voltage regulation behavior. Therefore, despite the opening definition being mostly correct, the reactive power response described in the statement is incorrect. References: ENTSO-E synchronous condenser technical sheet and power-system reactive compensation references.