Modern power systems, referred to as cyber-physical energy systems (CPESs), are complex systems with strong interdependencies between power and information and communication technology (ICT) systems. CPESs also have dependencies between the essential grid services. For instance, coordinated voltage control depends on state estimation, which depends on measurement acquisition. Due to the high relevance of these grid services for operating CPESs, assessing their performance is crucial for assessing the performance of a CPES. Most of these grid services are so-called ICT-enabled grid services, which means that they rely to a high degree on ICT. Accordingly, properties such as availability, correctness and timeliness, which depend on the involved software, hardware and data of the ICT system, must be considered for assessing the performance of an ICT-enabled grid service. Disturbances and repair actions in CPESs impact these properties, which can then propagate and affect the performance of a grid service as well as other dependent grid services. There is, therefore, a need for the ability to model the influence of the properties of software, hardware and data on ICT-enabled grid services for single services as well as across several services, resulting in a propagation of these parameters. This paper proposes a meta model for assessing the performance of ICT-enabled grid services, which can be instantiated for different grid services considering their dependencies. A multi-dimensional operational state space, which serves as a visualisation of the performance of grid services in terms of their state trajectory, is also proposed in this paper. These contributions enable new possibilities for planning and vulnerability analyses: property changes in parts of the ICT system can be simulated to investigate their consequences throughout the ICT-enabled grid services. This is demonstrated by a case study with a state estimation service considering an exemplary CPES and scenarios with disturbances. The performance of this state estimation service considering the disturbances is then investigated using the proposed meta model, and the change in performance is visualised as trajectories in the proposed operational state space.