SEL继电器SEL-387A特色应用及原理
Current Differential and Overcurrent Relay
The SEL-387A Current Differential and Overcurrent Relay offers restrained and unrestrained differential protection for two terminals. Second-, fourth-, and fifth-harmonic elements, augmented by the dc element, provide security during transformer energization and overexcitation conditions in a user-defined choice of either harmonic restraint or harmonic blocking. Overcurrent elements provide backup protection that contributes to the versatility of the SEL-387A.
sel-387a
电流差动和过流继电器
sel-387a差动电流和过电流继电器提供了内敛与奔放两端差动保护。二-，第四-，和第五次谐波成分，增加了直流分量，提供安全保障，在变压器通电和过励磁条件下在一个用户定义的选择谐波或谐波闭锁。过流元件提供备份保护，有助于对sel-387a通用性。
SEL继电器SEL-387A特色应用及原理
Two-Winding Current Differential Protection
The SEL-387A offers sensitive current differential protection with programmable single- or dual-slope percentage restraint, supervised by a choice of second- and fourth-harmonic blocking or restraint elements, plus fifth-harmonic and dc blocking elements for secure protection of up to two windings. Phase current harmonic blocking is set for either common or independent winding basis. Unrestrained high-set differential elements provide fast operation for high-magnitude internal faults. “Around the clock” phase angle compensation settings and automatic tap calculations simplify settings.
Individual Winding Overcurrent Protection
Torque-controllable overcurrent elements, including one instantaneous, one definite-time, and one inverse-time element each for phase, negative-sequence, and residual ground currents, provide comprehensive overcurrent protection on each winding input.
Through-Fault Recording and Monitoring
Through-fault duty is recorded and accumulated for use in SELogic control equations or manual monitoring.
Protection and Control Logic
Restricted Earth Fault (REF) logic provides sensitive grounded-wye winding ground fault protection. SELogic control equations with SELogic variables, timers, latch bits, and remote control elements are used for customizing advanced protection and control schemes. Local programmable control elements and programmable text display points provide an advanced local operator interface.
Metering and Reporting
Oscillographic event reports (up to seven 60-cycle reports), Sequential Events Recorder (SER) reporting, and accurate metering eliminate or reduce external recorder and metering requirements. Station battery voltage monitor and circuit breaker contact wear monitor provide important data for Reliability Centered Maintenance (RCM) programs. Use with the SEL-2600A RTD Module to meter temperatures from as many as 24 RTDs.
acSELerator QuickSet Software
Develop relay settings offline, program SELogic control equations, and analyze post-fault event reports.
SEL继电器SEL-387A特色应用及原理
SEL继电器特色应用
多绕组变压器电流差动保护与利用相结合的单多达四绕组或双斜率比率差动特性、过流保护和限制接地故障（REF）保护。是的sel-387a双绕组变压器保护的低成本的解决方案。
除了典型的变压器保护器、发电机、大型电机、等多端电源装置。提供备用配电母线或馈线保护与低侧过电流元件。
个别绕组过电流保护提供了全面的过电流保护，每个绕组输入转矩可控的过电流元件。
基于状态的维修可选的热监测，以激活一个控制动作或发出报警时，变压器有过多的绝缘老化或生命损失的危险。通过故障监测收集累积的故障数据，并安排主动维护。
