Saudi Arabian Grid Code May 2024

Operating Margin 4.4.6.1 In order to deal with Demand Forecast uncertainties and to safeguard against a sudden loss of Generation from the Transmission System, it is imperative that a suitable Operating Margin be maintained through the Control Phase. Operating Margin is required to have Capacity available in the System that can be utilized for reliable and secure balancing of supply and Demand. 4.4.6.2 Operating Margin is the additional output from Generating Plants or Demand Control which is realizable in real time to aid in containing and correcting any System frequency falling to an acceptable level due to loss of Generation or a mismatch between supply and Demand. 4.4.6.3 The Operating Margin consists of Operating Reserve (further divided into 3 categories, Primary, Secondary, and Tertiary Operating Reserve) and Contingency Reserve as further elaborated in the following paragraphs. 4.4.6.4 Operating Reserve Operating Reserve’s definitions relate to the time elapsed from the occurrence of an Event which has initiated a frequency disturbance. The definition of the time at which the Event is deemed to have occurred and other associated definitions are addressed in the terms and condition laid down under Operating Margin Policy. (i) Primary Operating Reserve (a) Generating Units providing Primary Operating Reserve for Frequency Regulation as a System Service shall operate in an automatic Frequency Sensitive Mode (also known as free- governor mode in the case of Synchronous Generating Units) for automatic response of the Unit’s Power output to changes in frequency. The Speed Governor Systems of the Synchronous Generating Unit shall have a maximum response time of five (5) seconds. The Active Power response of Power Park Modules to frequency deviations (Frequency Regulation) shall respond as fast as Chapter 4 - Operating Code The Saudi Arabian Grid Code Updated Version: May 2024 technically feasible with an initial delay that shall be as short as possible and no greater than two (2) seconds. The automatic change in Active Power output of a Generating Unit shall also increase or decrease in response to a System frequency decrease or increase. (b) The Positive Primary Response is the automatic increase in Active Power output of a Generating Unit in response to a System frequency fall in accordance with the Primary Control capability and additional mechanisms for releasing Active Power. The Negative Primary Response is the automatic decrease in Active Power output of a Generating Unit in response to a System frequency rise in accordance with the Primary Control capability and additional mechanisms for reducing Active Power output. (ii) Secondary Operating Reserve Secondary Operating Reserve is the additional MW output (and/or reduction in Demand) required compared to the pre-Incident output (or Demand), which is fully available and sustainable over the period from 15 to 90 seconds following an Event. (iii) Tertiary Operating Reserve Tertiary Reserve is further divided into Band 1 and Band 2, as explained below: (a) Band 1: additional MW output (and/or reduction in Demand) required compared to the pre-incident output (or Demand) which is fully available and sustainable over the period from ninety (90) seconds to five (5) minutes following an Event. (b) Band 2: additional MW output (and/or reduction in Demand) required compared to the pre-Incident output (or Demand) which is fully available and sustainable over the period from five (5) minutes to thirty (30) minutes following an Event. 4.4.6.5 Contingency Reserve Contingency Reserve is the margin of available Generation Capacity over Forecast Demand, which is required in the period from twenty-four (24) hours ahead down to real time, to cover against uncertainties in availability of