def reference_grid():

    ## PYPOWER Case Format : Version 2
    ppc = {'version': '2'}

    ##-----  Power Flow Data  -----##
    ## system MVA base
    ppc['baseMVA'] = 100

    ## bus data
    # bus_i type Pd Qd Gs Bs area Vm Va baseKV zone Vmax Vmin
    ppc['bus'] = array([
        [1, 3, 0, 0, 0, 0, 1, 1.06, 0, 100, 1, 1.06, 0.94],
        [2, 2, 21.7, 12.7, 0, 0, 1, 1.045, 0, 100, 1, 1.06, 0.94],
        [3, 2, 94.2, 19, 0, 0, 1, 1.01, 0, 100, 1, 1.06, 0.94],
        [4, 1, 47.8, -3.9, 0, 0, 1, 1.019, 0, 100, 1, 1.06, 0.94],
        [5, 1, 7.6, 1.6, 0, 0, 1, 1.02, 0, 100, 1, 1.06, 0.94],
        [6, 2, 11.2, 7.5, 0, 0, 1, 1.07, 0, 100, 1, 1.06, 0.94],
        [7, 1, 0, 0, 0, 0, 1, 1.062, 0, 100, 1, 1.06, 0.94],
        [8, 2, 0, 0, 0, 0, 1, 1.09, 0, 100, 1, 1.06, 0.94],
        [9, 1, 29.5, 16.6, 0, 19, 1, 1.056, 0, 100, 1, 1.06, 0.94],
        [10, 1, 9, 5.8, 0, 0, 1, 1.051, 0, 100, 1, 1.06, 0.94],
        [11, 1, 3.5, 1.8, 0, 0, 1, 1.057, 0, 100, 1, 1.06, 0.94],
        [12, 1, 6.1, 1.6, 0, 0, 1, 1.055, 0, 100, 1, 1.06, 0.94],
        [13, 1, 13.5, 5.8, 0, 0, 1, 1.05, 0, 100, 1, 1.06, 0.94],
        [14, 1, 14.9, 5, 0, 0, 1, 1.036, 0, 100, 1, 1.06, 0.94],
        [6661, 4, 0, 0, 0, 0, 1, 1.06, 0, 100, 1, 1.06, 0.94],
        [6662, 4, 0, 0, 0, 0, 1, 1.045, 0, 100, 1, 1.06, 0.94],
        [6663, 4, 0, 0, 0, 0, 1, 1.01, 0, 100, 1, 1.06, 0.94],
        [6664, 4, 0, 0, 0, 0, 1, 1.019, 0, 100, 1, 1.06, 0.94],
        [6665, 4, 0, 0, 0, 0, 1, 1.02, 0, 100, 1, 1.06, 0.94],
        [6666, 4, 0, 0, 0, 0, 1, 1.07, 0, 100, 1, 1.06, 0.94],
        [6667, 4, 0, 0, 0, 0, 1, 1.062, 0, 100, 1, 1.06, 0.94],
        [6668, 4, 0, 0, 0, 0, 1, 1.09, 0, 100, 1, 1.06, 0.94],
        [6669, 4, 0, 0, 0, 19, 1, 1.056, 0, 100, 1, 1.06, 0.94],
        [66610, 4, 0, 0, 0, 0, 1, 1.051, 0, 100, 1, 1.06, 0.94],
        [66611, 4, 0, 0, 0, 0, 1, 1.057, 0, 100, 1, 1.06, 0.94],
        [66612, 4, 0, 0, 0, 0, 1, 1.055, 0, 100, 1, 1.06, 0.94],
        [66613, 4, 0, 0, 0, 0, 1, 1.05, 0, 100, 1, 1.06, 0.94],
        [66614, 4, 0, 0, 0, 0, 1, 1.036, 0, 100, 1, 1.06, 0.94],
    ])

    ## generator data
    # bus Pg Qg Qmax Qmin Vg mBase status Pmax Pmin Pc1 Pc2 Qc1min Qc1max Qc2min Qc2max ramp_agc ramp_10 ramp_30 ramp_q apf
    ppc['gen'] = array([
        [1, 232.4, -16.9, 10, 0, 1.06, 100, 1, 332.4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
        [2, 40, 42.4, 50, -40, 1.045, 100, 1, 140, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
        [3, 0, 23.4, 40, 0, 1.01, 100, 1, 100, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
        [6, 0, 12.2, 24, -6, 1.07, 100, 1, 100, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
        [8, 0, 17.4, 24, -6, 1.09, 100, 1, 100, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
    ])

    ## branch data
    # fbus tbus r x b rateA rateB rateC ratio angle status angmin angmax
    ppc['branch'] = array([
        [1, 2, 0.01938, 0.05917, 0.0528, 9900, 0, 0, 0, 0, 1, -360, 360],
        [1, 5, 0.05403, 0.22304, 0.0492, 9900, 0, 0, 0, 0, 1, -360, 360],
        [2, 3, 0.04699, 0.19797, 0.0438, 9900, 0, 0, 0, 0, 1, -360, 360],
        [2, 4, 0.05811, 0.17632, 0.034, 9900, 0, 0, 0, 0, 1, -360, 360],
        [2, 5, 0.05695, 0.17388, 0.0346, 9900, 0, 0, 0, 0, 1, -360, 360],
        [3, 4, 0.06701, 0.17103, 0.0128, 9900, 0, 0, 0, 0, 1, -360, 360],
        [4, 5, 0.01335, 0.04211, 0, 9900, 0, 0, 0, 0, 1, -360, 360],
        [4, 7, 0, 0.20912, 0, 9900, 0, 0, 0.978, 0, 1, -360, 360],
        [4, 9, 0, 0.55618, 0, 9900, 0, 0, 0.969, 0, 1, -360, 360],
        [5, 6, 0, 0.25202, 0, 9900, 0, 0, 0.932, 0, 1, -360, 360],
        [6, 13, 0.06615, 0.13027, 0, 9900, 0, 0, 0, 0, 1, -360, 360],
        [6, 12, 0.12291, 0.25581, 0, 9900, 0, 0, 0, 0, 1, -360, 360],
        [6, 11, 0.09498, 0.1989, 0, 9900, 0, 0, 0, 0, 1, -360, 360],
        [7, 8, 0, 0.17615, 0, 9900, 0, 0, 0, 0, 1, -360, 360],
        [7, 9, 0, 0.11001, 0, 9900, 0, 0, 0, 0, 1, -360, 360],
        [9, 14, 0.12711, 0.27038, 0, 9900, 0, 0, 0, 0, 1, -360, 360],
        [9, 10, 0.03181, 0.0845, 0, 9900, 0, 0, 0, 0, 1, -360, 360],
        [10, 11, 0.08205, 0.19207, 0, 9900, 0, 0, 0, 0, 1, -360, 360],
        [12, 13, 0.22092, 0.19988, 0, 9900, 0, 0, 0, 0, 1, -360, 360],
        [13, 14, 0.17093, 0.34802, 0, 9900, 0, 0, 0, 0, 1, -360, 360],
    ])

    return ppc
