The criteria, algorithms and realization of several new types of microcomputer based protection are discussed in the paper, including two types of negative phase sequence directional power protection, second-harmonic current of exciting winding type and longitudinal zero-sequence voltage type, and single-element cross differential protection. 讨论了微机式新型转子二次谐波型负序功率方向保护、纵向零序电压型负序功率方向保护及单元件横差保护的判据、算法及有关实现方法。