SetThreadExecutionState... keeps your powershell script running without going to sleep

keepalive.cs

using System;
using System.ComponentModel;
using System.Runtime.InteropServices;

public static class Native
{
    public static EXECUTION_STATE? PreviousState { get; private set; }

    [DllImport("kernel32.dll", SetLastError = true, EntryPoint = "SetThreadExecutionState")]
    private static extern EXECUTION_STATE SetThreadExecutionStateNative(EXECUTION_STATE esFlags);

    public static void SetThreadExecutionState(EXECUTION_STATE esFlags)
    {
        if (esFlags.HasFlag(EXECUTION_STATE.ES_AWAYMODE_REQUIRED)
            && !esFlags.HasFlag(EXECUTION_STATE.ES_CONTINUOUS))
        {
            throw new ArgumentException("ES_AWAYMODE_REQUIRED must be used with ES_CONTINUOUS.");
        }

        EXECUTION_STATE previousState = SetThreadExecutionStateNative(esFlags);
        if (previousState == 0) throw new Win32Exception();
        PreviousState = previousState;
    }

    public static void Restore() => SetThreadExecutionState(PreviousState ?? EXECUTION_STATE.ES_CONTINUOUS);
}

[Flags]
public enum EXECUTION_STATE : uint
{
    ES_AWAYMODE_REQUIRED = 0x00000040,
    ES_CONTINUOUS = 0x80000000,
    ES_DISPLAY_REQUIRED = 0x00000002,
    ES_SYSTEM_REQUIRED = 0x00000001
}