DWR-IV Fully Automatic Anti-interference High Precision 0.0001Ω Ground Grid Resistance Tester for Substations

The DWR-IV Fully Automatic Anti-interference Ground Grid Resistance Tester is a high-precision instrument designed for measuring grounding resistance and related parameters in substations and other field applications. Featuring substantial power output, comprehensive functionality, portability, robust anti-interference performance, and exceptional accuracy, this integrated device incorporates a built-in frequency conversion power module with continuously adjustable output frequencies ranging from 45.0 Hz to 65.0 Hz, including specific variants such as 47.5 Hz/52.5 Hz, 45.0 Hz/55.0 Hz, 60.0 Hz, 65.0 Hz, 57.5 Hz/62.5 Hz, and 55.0 Hz/65.0 Hz. Equipped with a high-speed processor core and advanced digital filtering technology, it effectively eliminates interference from power-frequency electric fields, fundamentally addressing measurement challenges under strong electromagnetic interference conditions. Extensive field tests and user experiences confirm that the instrument delivers accurate, stable, and highly reproducible measurements even in harsh electromagnetic environments of operational substations, making it the ideal solution for characterizing grounding grid parameters in large and medium-sized systems.

The instrument primarily features the following characteristics:

• Super-large LCD display in Chinese
  The device features a high-end 7-inch full-touch LCD display and an intuitive touchscreen interface, offering simple operation with clear instructions at every step—making it user-friendly even without specialized training. A single tap completes the entire measurement process, establishing it as the ideal intelligent ground grid surveying equipment available today.
• Massive Data Storage
  The instrument is equipped with a calendar chip and high-capacity storage, capable of storing up to 100 data sets. It can save test results in chronological order, allow instant access to historical records, and support print output.
• Frequency conversion technology, precise measurement
  The instrument features strong anti-interference capability, with its built-in variable-frequency power module providing the measurement output power. It supports switching between multiple frequencies and employs digital filtering technology to effectively suppress various power frequency interference signals present in the field, ensuring high-precision, accurate, and reliable measurements.
• High-speed processor chip
  Highly accurate and rapid: The instrument employs a specialized fast digital signal processor as its core processing unit, significantly enhancing its computational capabilities while ensuring precise measurement data.
• Intelligent monitoring and control throughout the entire process
  powered by its high-performance internal processing core, the instrument rapidly and automatically performs a series of complex computational steps—including current output, voltage acquisition, and frequency conversion—throughout the entire measurement process. It can automatically determine the impedance of the current circuit and adjust the output current of the variable-frequency power supply (with maximum output current set via optional configuration), completing testing tasks without human intervention. The instrument measures ground network impedance, including its pure resistance and pure reactance components.
• PC-based data processing
  The data measured by the instrument can be exported via a USB drive and subsequently viewed and managed on a PC.
• Multiple Frequency Selections
  During instrument testing, you can select the appropriate frequency settings based on specific requirements.

Figure 3-1: Panel Appearance Layout Diagram

1. Power Supply Socket (AC 220V)
2. mains switch
3. printer
4. Emergency shutdown button: Disconnect the test output power supply. In case of emergencies during testing, pressing this button allows rapid emergency shutdown of all output power supplies without disconnecting the input power, ensuring safety for both personnel and equipment.
5. Full-touch LCD display: The large screen displays each step of the operation process in Chinese; users simply need to tap the corresponding area to automatically complete the entire measurement. As a precision component, the touch-sensitive LCD should be protected from prolonged sunlight exposure, heavy pressure, or scratches from sharp objects. Using a pencil tip or other pen-shaped plastic tool when operating the display enhances accuracy.
6. USB Interface: A USB drive slot that automatically imports all measurement data stored in the instrument into a USB drive and saves them as text files named after the date. These files can be viewed and used to generate reports on the user's computer using the included software. When the USB drive is inserted into the instrument's USB interface and data transfer begins, it must not be removed during the process; doing so may cause transmission errors or even damage the drive.
7. Voltage measurement ports P1 and P2 (black): Connect P2 to the ground network under test, connect P1 to the auxiliary voltage electrode, and measure the potential difference between the auxiliary electrode and the ground network at the interface of P1 and P2.
8. Power output ports C1 and C2 (red): Connect C2 to the ground network under test, and connect C1 to the auxiliary current terminal to form the test current circuit.
9. Grounding terminal: For safe grounding of the instrument.