<p>In this paper, an energy harvesting multi-antenna relay-assisted non-orthogonal multiple access (NOMA) network is investigated. Two users are selected and paired to communicate with the source over direct source-user links via a user pairing scheme. The multi-antenna relay adopts power-splitting-based simultaneous wireless information and power transfer (SWIPT) for energy harvesting, and it employs the selection combining (SC)/transmit antenna selection (TAS) scheme to assist data communication. The impact of non-ideal system limitations, such as hardware impairments, imperfect successive interference cancellation (ipSIC), outdated channel state information (CSI), and channel estimation error (CEE), on system performance is also considered. Closed-form exact and asymptotic expressions for the outage probability are derived, and the energy efficiency is also obtained. The theoretical results are validated by Monte Carlo simulations. The results demonstrate that the outage probability can achieve a diversity order proportional to the minimum number of antennas at the relay. These imperfect factors can degrade overall system performance except in some special cases of ipSIC. Outdated CSI and CEE have a more severe impact on the outage probability than hardware impairments and ipSIC. Although hardware impairments and ipSIC degrade system performance, they do not affect the diversity order within their respective effective value ranges. In contrast, outdated CSI can reduce the equivalent diversity order to one for the corresponding link affected by outdated CSI. When CEE exists in a link, it reduces the equivalent diversity order of that link to zero. Moreover, an outage probability performance floor may occur when CEE is present at the user side. However, increasing the number of receiving and transmitting antennas at the relay simultaneously can reduce the value of the outage probability performance floor. The optimal power-splitting ratio for SWIPT is not always identical for the two selected users, and it is also affected by the non-ideal system limitations in the relay links. With regard to energy efficiency, more antennas can improve the maximum energy efficiency. Furthermore, these imperfect factors degrade the maximum energy efficiency except for some special cases of ipSIC and lead to a higher transmit SNR required to achieve the maximum energy efficiency.</p>