WBH-801A_Xuji microcomputer transformer protection device

1 Overview

1.1 Scope of Application

The WBH-801A microcomputer transformer protection device is suitable for transformers with various voltage levels of 220kV and above.

The WBH-801A device integrates all electrical quantity protection of a transformer. It can meet the requirements of dual main and dual rear configurations for transformers of various voltage levels and different wiring methods, as well as fully independent configurations for non electrical protection. This manual provides instructions for the WBH-801A device when used in a 220kV system.

1.2 Product Features

Based on the high-performance and highly redundant Xuji next-generation hardware platform, visual logic development tools are used to achieve transparent protection design. The principle of variable action characteristics comprehensively improves protection performance. The main features of this protection device include the "log system" and "black box" fault location technology for device memory.

1.2.1 Protection Performance

Reliable ratio differential protection

By using a multi segment and multi line method, it is possible to quickly remove serious faults within the area, while also ensuring sensitivity to minor and complex faults. The use of multiple algorithms combining long and short data windows greatly improves the software's anti-interference ability.

Advanced criteria for excitation inrush current

When the transformer is closed without load, the phase current is used to distinguish the excitation inrush current, avoiding the influence of other phase excitation inrush currents on the excitation inrush current of the current phase during the phase compensation process of the transformer. The characteristics of the inrush current are more distinct, and the differential protection is more reliable; Adopting a unique patented technology for fault identification during the airdrop process of the main transformer, and based on comprehensive open criteria, the dynamic protection can quickly operate during airdrop with faults.

Reliable TA saturation criterion

Based on the physical characteristics of TA exiting saturation at the zero crossing of the current, the differential sampling value is used as the TA saturation criterion to greatly improve the anti TA saturation ability of differential protection. When an external fault occurs and the normal time of the current waveform is ≥ 2.5ms, the differential protection is reliable and does not malfunction.

High sensitivity incremental differential protection

Equipped with incremental differential protection, it is not affected by load current, has high sensitivity, strong resistance to TA saturation, and can sensitively respond to minor inter turn short circuits and winding high resistance grounding faults.

Flexible protection configuration

Modular design of the program, the protected configuration can be flexibly configured according to user requirements using the dedicated configuration tool Prate-800A.

1.2.2 High performance and high redundancy Xu Ji's next-generation software and hardware platform

High performance and high reliability hardware structure

Adopting a hardware structure with 3 CPUs working in parallel, using a 32-bit high-performance DSP processor, 32-bit logic processor, and 16 bit high-speed AD, the protection outlet tripping adopts a "start+protection action" method to prevent misoperation caused by hardware failure of the protection device.

Strong anti-interference ability

Adequate anti-interference measures are taken in the design of software and hardware, with a 6U fully enclosed chassis, an overall panel, and strict separation of strong and weak electricity. The anti-interference ability of the device is greatly improved, and the external electromagnetic radiation also meets relevant standards.

Powerful self checking function

A complete A/D sampling circuit self-test can avoid device misoperation caused by A/D sampling errors; Open circuit self-test can accurately detect any open circuit disconnection or open circuit breakdown fault, issue an alarm, and reliably lock protection; Fixed value self-test can detect errors in the fixed value storage area, fixed value exceeding limits, etc; Equipped with+5V and ± 15V power self-test function, the device sends an alarm message and locks protection when the power supply voltage is abnormal.

Visual logic development

The visualized logic development tool VLD, in which all protection logic is composed of different visualized flexible relays, achieves complete transparency design of microcomputer protection.