Intelligent (Power Self-Powered) Passive Protection Device
ST260M protection device is an upgrade production based on ST260N intelligent (self-powered) passive protection device. With many of patented technologies and each technical index is greatly improved, it is very suitable for substation station working in harsh outdoor conditions and unmanned.
ST260M intellectual protect device adopts high integrated micro-processor with bus in the chip to process the signals of the current transformers, and output signal is controlled through digital logical calculation. with characteristics as compact structure, airproof chassis, maintenance-free design, and anti-interference performance, the device is specially suitable for power ring-grid cubicle in worse environment and insufficient installation space. 
• Low power-consumption design technology is adopted for the whole machine, to ensure start-up the protection functions quickly and reliably at any conditions.
• The structure of the device is simple and smart, easy and flexible to install, suiting for the compact installation conditions of ring power grid. 
• Power self-supply function (powered by current transformer) is available, which could avoid installation of DC screen or UPS with extra cost.
• A variety of selections for IEC standard Inverse-Curve, also, zero-sequence (grounding) current protection is comprised in device ST260M. 
• Inrush current blocking function is provided to prevent error tripping due to transformer switching without load.
• A fast algorithm of Short Data Window is used for Instantaneous protection to ensure rapid removal short-circuit fault and avoid over-grade trip.
• Rotate-code-switch are adopted to set parameters in device, it assure that the setting value are visual、stable、reliable and the setting step is fine with high precision characteristics.
• Current measurement circuit is designed with automatic-dynamic-gain, so the device has an extremely wide measuring range to respond the secondary rated value of 1A or 5A in transformers current. 
• Both 50Hz and 60Hz system are customized by the user; besides, tripping impulse output forms are also customization.
• The designation of both Enhanced energy-taking circuit and strong peak voltage absorption circuits ensure power-supplying circuit safe and reliable.
• Hybrid voltage such as accessing CT as power self-supply and DC24V or DC48V voltage.
• The designation of a very wide temperature range 、waterproof and dustproof ensures reliable operations under extreme ambient conditions.
• The device could record at least 100 times of historical events record read by special software for easy traceability. 
• Device ST260M provides RS-485 communication port and communication protocols is provided to clients so as to realize SCADA function.