The wireless sensor nodes used for monitoring the condition of grid equipment always be powered by disposable batteries. However, it introduces disadvantages, such as inconvenient replacement, short lifespan, and envi-ronmental pollution, significantly impeding the development of smart grids. Here, a high-performance piezo-electric vibration energy harvester (PVEH) is employed to the wireless monitoring system as the new intelligent equipment for grids. The system primarily consists of a double-crystal PVEH; a multi-functional power man-agement circuit (PMC) with maximum energy extraction, battery replenishment, and cold-start; a module for temperature sensing; and a micropower wireless section. The results show that the PVEH reaches an output voltage of 0.7 V under 0.02 g, which has ultra-low activation acceleration compared to other double-crystal PVEH. The PVEH with an integrated PMC can charge a 680-& mu;F capacitor to 3.3 V in 120 s, demonstrating over a 33.3% reduction in the charging time and a 50% enhancement in the charging efficiency. Moreover, the energy harvesting via the system can trigger the sensor once per 25 s, allowing the sensor to continue working and achieving the goal of intelligent monitoring. This study establishes a theoretical and experimental basis for PVEH-based sensor systems in the grid, thereby accelerating the application and commercialization of PVEH.