The basic function of an electric power system is to satisfy the system load requirement as economical as possible and with a reasonable assurance of continuity and quality. In order to achieve the required degree of reliability, power system managers, planners, designers and operators have utilized a wide range of criteria in their respective areas activities. This paper presents the impacts of HVDC link on the existing EEP's AC transmission system reliability. The criteria used for the indication of HVDC link performance is Equivalent Short Circuit Ratio(ESCR).It is a common parameter used to indicate the electrical strength or weakness of an AC/DC interconnection. Even if Ethiopia-Kenya high voltage direct current HVDC power system interconnection is under construction no system study is performed by EEP. To achieve this objective, EthiopiaKenya high voltage direct current HVDC power system modeled and integrated to existing HVAC system by using PSS/E software tool and simulation is carried out for system fault level. This was done by assessing the obtained results on system fault levels, comparing obtained result with preset ESCR value. The value of ESCR is 3.8 when the system is subjected to three phase fault. When the system is subjected to line to ground fault, the ESCR value has become 1.84. Finally, when the system is subjected to line to line fault an ESCR value of 2.33 was found. It was found that the system operates safely only in the case of three phase fault. For the rest cases the system couldn't operate properly because the existing HVDC system is weak. The integration of the HVDC scheme has negative impact on system reliability unless proper reactive power support installed.