Safety is paramount in the production process, especially for hazardous operations. When performing maintenance on high-voltage lines during power outages, the regulations of power outage, voltage testing, and grounding must be followed before commencing operations. Voltage testing must be performed using a voltage detector. A voltage detector is a common electrical safety tool used to detect the presence of voltage on electrical equipment. It confirms that the equipment is indeed de-energized before proceeding with other operations, preventing serious accidents such as installing grounding wires while the equipment is energized (closing grounding switches) or accidentally touching energized equipment. Therefore, the role of voltage detectors in the power industry is indispensable. Project Background Non-contact voltage detectors do not directly contact high-voltage lines. They utilize the electric field near the high-voltage line to detect whether the line is energized, displaying an indicator light to indicate whether it is energized or not. They can also send monitoring information to monitoring equipment. This device is fixedly installed on a pole of a section of high-voltage line outdoors. It is powered by AC or DC power, eliminating the need for battery replacements. Therefore, it can be used to detect whether a high-voltage line is energized and for long-term monitoring of high-voltage line operations. The device is equipped with a waterproof box, fully meeting the requirements for outdoor operation. The voltage detector developed this time is mainly used for monitoring high-voltage transmission lines in railways. Its design requirement is to monitor the operation of 27.5kV voltage lines in railways. Shortcomings of Non-Contact High-Voltage Voltage Detectors The voltage detector mentioned above has been put on the market and has been operating well. However, due to inherent limitations, its performance and functionality are not yet perfect. Based on customer feedback and on-site investigations, the following shortcomings were found: The sensor signal reading is unstable; the signal is weak in rainy weather and strong in sunny weather, which is detrimental to the normal operation of the detector; The detector lacks its own power supply, forcing it to be installed near a mains power source; The reliability and stability of the detector need improvement; The signal sent by the detector to the computer is unstable. To improve system stability and overcome the limitations of the operating environment, it is necessary to improve the structure of the detector's power supply, sensors, and circuitry to enhance its performance. Improvements to Non-Contact High-Voltage Detectors 1. Power Supply Improvement High-voltage lines and 220V AC mains power are typically installed separately. High-voltage lines are generally installed in open areas or sparsely populated areas, while 220V AC mains power is usually installed in towns or villages. Only in special locations are both high-voltage and AC mains power lines installed simultaneously. The detector previously described uses either 220V AC or 110V DC mains power, which limits its application space and significantly reduces its market value. To overcome these limitations, this paper improves the detector's power supply by using a combination of solar panels and batteries. The solar panels are TSM-10M batteries manufactured by Shanghai Jiaotong University Taiyang Green Energy Co., Ltd., and the batteries are GHB-6FMO.8 batteries manufactured by Nanjing Haige Technology Co., Ltd., which provide a 12V DC operating voltage. Combining the solar panels and batteries provides the entire device's power supply. On sunny days with ample sunlight, the solar panels operate, providing a 12V DC operating voltage to the entire circuit and the batteries. The batteries charge, and at night or when sunlight is less abundant, the batteries power the entire circuit. The improved electroscope does not require a 220V AC mains power supply and can be installed at any high-voltage line. 2. Sensor Improvement The sensor is used to read the electric field signal and is the signal source of the entire device. Previously, the sensor signal was weak in rainy weather due to rainwater. This paper improves the sensor housing by adopting a smooth hemispherical shell, as shown in Figure 1. The upper part of the figure is the hemispherical top cover, with a smooth surface that allows rainwater to easily slide off. The lower part is the base, with a 1cm diameter through-hole in the center through which the sensor signal line is led out. There are 5mm diameter dark holes on both sides of the through-hole for fixing the sensor. The top cover and base fasten together to effectively protect the sensor, and rainwater can slide off the top cover without forming a water film on the top, thus preventing interference with the sensor signal. In addition, two ground wires are led out from the sensor: one for the signal ground and the other for the indicator light and the relay controlling the computer signal transmission in the circuit. This ground wire is used to detect whether the signal line is intact. If the signal line is broken, the indicator light will also be broken. Without a ground wire, the indicator light will not illuminate, and the computer's signal transmission line will also be broken. This means both the power and no-power indicator lights will be off, and the power and no-power signals transmitted to the computer will be simultaneously cut off, preventing the transmission of erroneous signals and improving system reliability. This avoids sending erroneous no-power signals when the signal line is broken, which could cause accidents. Figure 1 shows the sensor housing. 3. Circuit Structure Improvement The circuit structure improvement also aims to enhance system reliability and prevent the transmission of erroneous signals. The previous section used a single-channel signal processing circuit. If this circuit malfunctions due to component aging or other reasons after prolonged operation, it may send erroneous signals, especially incorrectly sending a power signal as a no-power signal, which could lead to incalculable consequences. Therefore, this paper modifies the signal processing circuit to a dual-channel crossover operation. The two signal processing circuits are completely identical. Cross-validation is performed before the final signal is sent to the indicator light and computer. That is, only when both signals simultaneously indicate power (or no power) can the power (or no power) signal be sent to the indicator light and computer. If the two final signals are inconsistent, the final signal will be cut off and cannot be sent to the indicator light and computer. This indicates a malfunction in the voltage detector, prompting vigilance and appropriate measures to prevent accidents. 4. Improvement of Signals Sent to the Computer Previously, the signal was sent to the computer via the voltage detector. This raises the issue of a common ground wire. For the computer to correctly identify the signal from the voltage detector, the computer and voltage detector must share a common ground wire. Otherwise, a long transmission line without a common ground wire will cause the computer to misidentify the signal. This paper modifies the signal transmission method. As shown in Figure 2, the computer sends the signal, and the electroscope internally controls the connection or disconnection of energized or de-energized circuits via relay switches. The computer receives two signals sent by itself through the relay switches. If an energized circuit sends a high-level signal, the de-energized circuit sends a low-level signal, indicating that the high-voltage line is energized; if a de-energized circuit sends a high-level signal, the energized circuit sends a low-level signal, indicating that the high-voltage line is de-energized. If both circuits send either a high-level or low-level signal, the circuit malfunctions. [align=center]Figure 2 Signal Transmission[/align] Conclusion The improved electroscope device exhibits significantly improved signal stability compared to the previous version, with a marked reduction in signal fluctuation amplitude. Furthermore, the use of a dual-path crossover circuit greatly enhances the reliability of the electroscope system. Finally, the introduction of solar cells eliminates the need for 220V AC mains power, freeing the electroscope from the constraints of its operating location and increasing its market value.