Reactive power evaluation for non-sinusoidal systems has always been a matter of discussion for the electrical engineering community. To further this, a novel power theory called "Instantaneous Phasor Components Theory (IPCT)" is proposed in this work. The proposed theory provides definitions for instantaneous active power, instantaneous reactive power, and reactive power for sinusoidal and non-sinusoidal systems. A comparative analysis with the presently accepted standard definition and definitions given by other prominent power theories has been presented. The proposed power theory is validated through experimental studies. A single-phase DSTATCOM is controlled using IPCT to achieve sinusoidal, unity power factor source current in a non-sinusoidal system. Electrical transformations play a vital role in electrical engineering and are ubiquitously seen in prominent power theories. To bring academic clarity and understanding, a "Generalized Theory of Transformations" is proposed in the work.