电压保护继电器(VPR-A)是一种可以在正常或干扰条件下测量线路或相位有效值电压的继电器。微处理器对这些信息进行内部处理,以采取ANSI或IEC标准定义的电压保护措施。VPR-A提供的不同功能可分为以下几组:应用:-保护发电机,电机和变压器,对抗不利的系统电压条件。-监督自动转换转换方案。保护:—在一定时间内选择保护曲线。-定时和瞬时欠压(ANSI 27t/27i)。—剩余欠压(ANSI 27r)。-定时和瞬时过电压(ANSI 59t/59i)。—同极过电压(ANSI 59N)。—电压不平衡(ANSI 46)。 - Overfrequency and underfrequency (ANSI 81). - Phase reversal (ANSI 47). - Five (5) output relay programmable. - Loss of control volts relay. Digital Measurement: - RMS line or phase voltages. - Line or phase voltage unbalance. - Average voltage. - Supply frequency. - Phase sequence. Signaling and Programming: - LED and LCD display indication. - Touchpad programming. - Indication and storage of fault conditions and their values. - Undervoltage/overvoltage/unbalance/frequency pickup indicators for calibration testing