Short-Term Photovoltaic Power Generation Forecasting Based on Multivariable Grey Theory Model with Parameter Optimization

Table 2

Analysis of forecasting results on September 23.

	Date	Real value (kWh)	Ordinary model		Optimization model
			Recovered value (kWh)	Percent error (%)	Recovered value (kWh)	Percent error (%)
Sample data	9.15	539	539	0	539	0
	9.16	535	455.31	14.89	522.15	2.40
	9.17	558	596.68	6.93	558.37	0.07
	9.18	586	594.22	1.40	583.68	0.39
	9.19	546	550.63	0.84	552.39	1.17
	9.20	506	509.53	0.70	514.81	1.74
	9.21	507	512.50	1.08	517.88	2.15
	9.22	473	465.98	1.48	472.72	0.06
Forecasting data	9.23	123	81.65	33.62	105.84	13.95