POWER_STATE - NtDoc

Native API online documentation, based on the System Informer (formerly Process Hacker) phnt headers
#ifndef _NTPOAPI_H

typedef union _POWER_STATE
{
    SYSTEM_POWER_STATE SystemState;
    DEVICE_POWER_STATE DeviceState;
} POWER_STATE, *PPOWER_STATE;

#endif

View code on GitHub

This union is documented in Windows Driver Kit here and here.