In response to the secondary test requirements of substations in power systems, especially the distributed measurement demand of secondary analog quantities in smart substations, Wuhan Haomai has independently developed the YD-300 Wireless Telemetry Voltage-Current Phase Indicator, an intelligent multi-functional tester consisting of a test host and slave units.

△ YD-300 Wireless Telemetry Voltage-Current Phase Indicator

1. Host Tester

It adopts a master-slave processor architecture. The slave processor is equipped with an advanced processing chip plus high-precision, high-speed synchronous sampling chips; the master processor motherboard features a quad-core processor with an Android operating system and a 7-inch capacitive touch color LCD screen. Built with a large-capacity lithium battery, it can work continuously for more than 6 hours without an external power supply, and supports data import and export via a USB flash drive. Its functional modules mainly include automatic testing, basic testing, intelligent diagnosis and other test items.

2. Slave Tester

It has no display screen and is mainly used for data collection and upload, with a built-in USB interface. It has a frequency range of 45～55Hz and a wireless communication distance of about 1000m. For the interface indicator lights: press and hold the power button for 3 seconds, and the running indicator light will turn on; if a voltage input higher than 10V is detected, the alarm indicator light will turn on.

1 Working Principle

Voltage and current measurements at multiple points within a distance of 1600m can be performed by YD-300 slave units at each point through wireless repeaters for synchronization and signal relaying, with a data concentrator uniformly receiving and managing the data. The data concentrator is connected to a PC via a USB port, and data collection and aggregation can be realized after installing the dedicated program, with the voltage of one slave unit as the reference and its amplitude and phase displayed in a centralized manner. Multiple repeaters can be added to amplify the signal according to the signal strength. All test data can be imported and exported, and test reports generated in a specific format. The data collected by a single PC can be uploaded to the cloud for viewing on other devices.

2 Test Principle

The multi-point YD-300 background system realizes unified management of test schemes, including scheme import and export, data synchronous upload, viewing and editing, etc. Click to enter a specific test scheme, select the test content, initial parameters of the test device and the status of slave units. After clicking Start Test, the parameters are updated in real time, and two items can also be checked for visual differential comparison. The radar phasor diagram can be viewed to intuitively display the amplitude and phase values. The setting of reference values and one-click calibration function reduce calculation errors with a reasonable error range set. The ratio management function controls the value conversion between the high and low voltage sides for rational output, and the data is uploaded to synchronize the information on the server.

3 Test Method

1. Configure and generate presets for each test case through the multi-point voltage-current phase test platform, which can be created and synchronously imported based on existing templates. A structural mapping diagram of the scheme is automatically generated according to template parsing.

2. Before starting the test, the structural system of the scheme can be customized and modified. The system reads data received from remote ends by default, and the amplitude, phase and reference values can be modified, with the first slave unit as the default reference value. Additional slave units can be added on this page according to the number of on-site slave units.
3. On-site deployment: Set different addresses for multiple YD-300 slave units via the DIP switches on the panel, which adopt the 8421 binary-coded decimal system—bits are low to high from left to right, with the switch down for "1" and up for "0". For example, if the DIP switch is set to 1100, the address of the slave unit is 3. If the distance is too long or the signal is weak, install a repeater on the slave unit to extend the signal reception range.
4. Status check: View the status of each slave unit—a green icon indicates online status, and a gray icon indicates offline status.
5. Execute test command: After starting the test, the received data is calculated and finally presented to the user based on the reference value, error value, current ratio and voltage ratio set before the test. To ensure consistency between cloud data and local test data, execute the data upload function for automatic network synchronization.

The YD-300 Wireless Telemetry Voltage-Current Phase Indicator enables data collection at multiple points in a substation without the need for on-site back-and-forth recording. One-time deployment is realized with synchronization via wireless repeaters and unified data reception and management by the concentrator, achieving one-to-many management and control of devices. All collected data is stored in the cloud and can be read locally. Meanwhile, all test data can be imported and exported with test reports generated in a specific format, bringing great convenience to on-site applications and winning unanimous recognition and praise from user units.