With the rapid development of the power grid scale, the workload of protection equipment verification has increased sharply, and the demand for intelligence has become higher and higher. Traditional on-site verification is generally carried out step by step by on-site engineers in accordance with operation instruction documents, and there are the following status quo in practical applications:

Heavy on-site operation workload and low efficiency;

Difficult on-site supervision;

The currently widely used on-site verification equipment has insufficiently intelligent test operations and requires high professional levels of technical personnel.

In response to the above status quo, Wuhan Haomai Electric Power has designed and developed an automatic closed-loop testing platform for protection devices in smart substations, realizing closed-loop one-click automatic testing of protection devices and providing a faster and more efficient solution for on-site verification.

Closed-Loop Testing

Traditional relay protection testers adopt open-loop testing with protection devices, and there is no feedback information from the protection devices. The automatic closed-loop testing platform for protection devices in smart substations can receive the status upload of protection devices, automatically carry out test items, output digital/analog quantities to the protection devices, and receive MMS messages returned by the protection devices to form a closed-loop test. Based on the MMS message format of the IEC61850 standard, it performs read-write control on the protection device model, views online information such as settings, soft pressure plates, and system parameters of each protection device, subscribes to the message information output by the protection device, and forms closed-loop information collection and control.

△ Schematic Diagram of Closed-Loop Testing Complete Machine

One-Click Automatic Testing

On the basis of closed-loop information collection and equipment control of protection and management units, a customized test case library is established. Through MMS client technology, the test platform realizes real-time interaction with protection devices and conducts automatic tests. After the test is completed, it automatically generates protection setting test case results.

△ Full-Automatic One-Click Testing Technical Process

Test Scheme Module - Custom Mode

One-click configuration for quick and convenient operation: In custom mode, only the pressure plate switching and settings need to be configured, and the system automatically calculates the measured values. In this mode, the output of test items can be automatically calculated only by inputting setting values, fault current, zero-sequence sensitive angle and zero-sequence compensation coefficient. The calculation method is derived from the pre-imported test scheme or expert database scheme, and it does not have the function of editing short-circuit calculation.

Test Scheme Module - Expert Mode

Supports short-circuit calculation and expert scheme import: Expert mode can perform scientific configuration by setting relevant coefficients and setting values of short-circuit calculation to complete test verification. This mode supports one-click import of mainstream manufacturers' test schemes and short-circuit calculation. By setting parameters such as fault type, fault direction, short-circuit impedance multiple, calculation model, short-circuit current value, zero-sequence compensation calculation amplitude and phase angle, it calculates different output voltage, current, amplitude and phase values (i.e., UA, UB, UC, IA, IB, IC) according to different test types.

Functional Advantages

1. Realizes the transformation from "manual experience" to "intelligent judgment" in prediction. The equipment failure rate has decreased by 75% compared with the same period, and the equipment availability factor is as high as 99.988%, greatly improving equipment stability.
2. Realizes the transformation from "passive operation and maintenance" to "active operation and maintenance". Timely grasp the equipment status and accurately determine the operation and maintenance objects. Taking the comprehensive inspection of 20 protection screen cabinets as an example, the single inspection time is shortened from 2 hours manually to 20 minutes by intelligent inspection, and the operation and maintenance efficiency is improved by 83%.
3. Realizes the transformation from "post-event response" to "pre-event prevention" in emergency handling. Use the background data management system for remote analysis to predict and handle hidden dangers and defects in advance, and the emergency response speed is increased by more than 70%.
4. Realizes the transformation from "decentralized on-site" to "intensive remote" in management and control. Use the data upload platform to real-time grasp the operation status of secondary protection devices within the jurisdiction, realize remote real-time interaction between the monitoring center and the emergency site, and the accident handling speed is increased by more than 90%.