How can intelligent measuring circuit breakers avoid the risk of malfunction when multiple power sources are connected to the grid?
Publish Time: 2025-11-25
With the advancement of the "dual carbon" goal and the transformation of the energy structure, distributed energy resources are being integrated into the distribution network at an unprecedented rate. Traditional power grids are designed based on unidirectional power flow, but the widespread penetration of distributed energy resources is gradually transforming the distribution network into a complex network with multiple power sources and bidirectional power flow. Against this backdrop, circuit breakers, as the last line of defense for the power system, especially intelligent measuring circuit breakers widely used in highways, subways, factories, ports, and office buildings, are crucial.When a short circuit or overload occurs, the circuit breaker quickly cuts off the power supply to protect appliances and your family. However, in systems containing distributed power sources, the source of fault current is no longer singular. For example, when a short circuit occurs on the main grid side, not only will the main substation provide short-circuit current, but local photovoltaic inverters or energy storage converters may also inject reverse current into the fault point. This multi-source superimposed current characteristic is easily misjudged by traditional circuit breakers as a fault on their own side, thus triggering unnecessary tripping, causing unplanned power outages, and affecting power supply continuity and user satisfaction.To address this challenge, the intelligent measuring circuit breaker effectively mitigates the risk of malfunctions in multi-power source scenarios through three core technological approaches:1. Intelligent Protection Logic Based on Directional DiscriminationTraditional thermal-magnetic circuit breakers operate solely based on current amplitude, unable to distinguish current direction. The intelligent measuring circuit breaker, however, incorporates high-precision current/voltage sensors and a microprocessor, enabling real-time calculation of power flow and fault direction. By introducing directional overcurrent protection, the system can determine whether the short-circuit current originates from the local load or the external power grid. For example, if the detected current exceeds a threshold but flows "from outside to inside," and the local distributed power source has no abnormal output, it is determined to be a remote fault, and no tripping occurs. Conversely, if the current flows from the local distributed power source to the fault point, a comprehensive decision is made based on other criteria. This directional recognition capability significantly improves the selectivity of protection, effectively avoiding "over-level tripping" or "innocent tripping."2. Adaptive Setting and Dynamic Threshold AdjustmentDistributed energy output is intermittent and fluctuating, causing the normal operating current baseline to constantly change. If fixed settings are still used, overload malfunctions are easily triggered during periods of high photovoltaic power generation or energy storage discharge. Intelligent measuring circuit breakers communicate with energy management systems or local controllers to obtain real-time operating status of distributed power sources and dynamically adjust the activation thresholds and time limits for overload and short-circuit protection. For example, they automatically increase short-term overload tolerance during periods of sufficient sunlight and restore normal sensitivity at night or on cloudy days. Some high-end products even employ machine learning algorithms to predict future current trends based on historical load and power generation data, achieving "predictive protection" and maximizing power supply reliability while ensuring safety.
