## 6 Conclusions
### Nomenclature  
\(\rho\) & the conversion efficiency of energy storage  
\(E_{r}\) & the released energy of energy storage  
\(E_{s}\) & the stored energy of energy storage  
\(E_{total}\) & the total required energy of an energy Internet system  
\(E_{basic}\) & the demand of fixed basic energy  
\(y\) & the total number of energy storage  
\(e_{i}\) & the basic requirement for each energy storage  
\(l\) & the number of energy storage in energy Internet  
\(x_{i}\) & the stored energy of each energy storage  
\(E_{real}\) & the required energy for real-time  
\(E_{non-real}\) & the required energy for non-real-time  
\(C\) & the total cost  
\(C_{imin}\) & the minimum value of the \(i\)th energy storage cost  
\(C_{imax}\) & the maximum value of the \(i\)th energy storage cost  
\(f\) & the selection of cost according to actual situation  
\(E\) & the total stored energy of all energy storages in EI system  
\(E_{RE}\) & the energy released by various energy networks  
\(E_{SE}\) & the energy stored by energy storages  
\(E_{CE}\) & the consumed energy  
\(X_{imax}\) & the maximum storage capacity of each energy storage  
\(\rho_{i}\) & the energy conversion efficiency of the \(i\)th energy storage  
\(n\) & the number of particles  
\(j\) & the \(j\)th particle in PSO  
\(d\) & the dimension of search space  
\(t\) & the number of iterations  
\(v_{t}\) & the velocity at the \(t\)th iteration  
\(q_{t}\) & the position at the \(t\)th iteration  
\(w\) & the inertia weight  
\(c_{1},c_{2}\) & the acceleration constants  
\(r_{1},\ r_{2}\) & the random values in the range [0,1]  
\(p_{best}\) & the best previous position of a particle  
\(g_{best}\) & the value of the best particle among all the particles  
\(\alpha\) & an agent in MAPSO  
\((a,b)\) & the specific location of an Agent in the global environment, and a, b are the global  
environment boundaries of MAPSO  
\(A_{m,n}\) & the agent with position \((m,n)\)  
\(N_{m,n}\) & the local environment of \(A_{m,n}\)  
\(M_{m,n}\) & the agent with the minimum fitness value among 8 neighbors of \(A_{m,n}\)  
\(rand(-1,1)\) & a random number in the range [\(-1,1\)]  
\(\gamma\) & the united objective function  
\(\theta_{c}\) & weight coefficients of objective function \(C\)  
\(\theta_{e}\) & weight coefficients of objective function \(E\)  
* [PERSON] et al. (2017) [PERSON]; [PERSON]; [PERSON]; [PERSON] [PERSON] Experimental investigation of a new smart energy management algorithm for a hybrid energy storage system in smart grid applications. _Electr. Power Syst. Res._**2017**, _144_, 185-196. [CrossRef]
* [PERSON] et al. (2016) [PERSON]; [PERSON]; [PERSON]; [PERSON] Shared energy storage management for renewable energy integration in smart grid. _arXiv_**2016**, \(5\), 1-5. * [PERSON] (2011) [PERSON] Electronic controlled energy storage devices and applications in future smart grid. _J. Electron. Sci. Technol._**2011**, \(9\), 3-8. * [PERSON] et al. (2018) [PERSON] [PERSON]; [PERSON] [PERSON]; [PERSON] [PERSON]; [PERSON] [PERSON] State-of-art review of the optimization methods to design the configuration of hybrid renewable energy systems (HRESs). _Front. Energy_**2018**, \(1\), 1-32. [CrossRef]
* [PERSON] et al. (2013) [PERSON]; [PERSON]; [PERSON] Smart coordination of energy storage units (ESUs) for voltage and loading management in distribution networks. _IEEE Trans. Power Syst._**2013**, _28_, 4812-4820. [CrossRef]
* [PERSON] et al. (2015) [PERSON]; [PERSON]; [PERSON]; [PERSON]; [PERSON]; [PERSON] Coordination of multiple energy storage units in a low-voltage distribution network. _IEEE Trans. Smart Grid_**2015**, \(6\), 2906-2918. [CrossRef]
* [PERSON] et al. (2017) [PERSON] [PERSON]; [PERSON] [PERSON]; [PERSON] [PERSON]; [PERSON] [PERSON]; [PERSON] [PERSON] Optimal cooperative management of energy storage systems to deal with over- and under-voltages. _Energies_**2017**, _10_, 293. [CrossRef]
* [PERSON] et al. (2016) [PERSON]; [PERSON]; [PERSON] Coordination of multifunctional distributed energy storage systems in distribution networks. _IET Gener. Transm.