High-voltage direct current (HVDC) system plays a pivotal role in model power systems. The system’s condition monitoring and fault prediction are also receiving more attention, facilitated by the development of the Internet of Things (IoT) and sensor technology. Ideally, sensors used in HVDC systems should be battery-free and maintenance-free. To realize this, vibration energy harvesters can be a solution. In this work, we proposed an electric model for a vibration harvester that can be used to harvest the vibration energy in the HVDC converter valve. The advantage of this model lies in its simplicity and the easy availability of its parameters. We first verify the proposed model by comparing the simulation results with the expected performance given in the datasheet of the vibration harvester. Furthermore, by using the vibration data in the field, we compare the simulation results from the proposed model with the actual experiment measurements of the vibration harvester. The results validate the effectiveness and accuracy of our model, and demonstrate the feasibility of using vibration harvesters to power sensors for HVDC converter valves.