Saudi Arabian Grid Code May 2024

Protection Equipment/Schemes 2.5.2.1 All Users shall be responsible for providing Protection for the Equipment and facilities at their respective sides when connected to the Transmission System. 2.5.2.2 All User Protection Schemes, relays and their settings, shall require prior coordination with and approval of the TSP’s relevant Protection engineering office. 2.5.2.3 The Protection Schemes shall isolate the faulty section and Equipment in case of Fault with the dependability, selectivity, speed, and sensitivity as defined in the applicable Connection Agreement or the Grid Code. 2.5.2.4 The protective Equipment connected to the Transmission System shall be tested to achieve the specified level of dependability, selectivity, speed, and sensitivity in Fault clearing and to minimize the impacts on the Grid. 2.5.2.5 The Protection Scheme’s ability to initiate the successful tripping of the circuit breaker which is associated with the faulty Equipment shall be measured by System Protection Dependability Index exceeding 99%. 2.5.2.6 Users shall comply with the following requirements for Fault clearance times (from Fault inception to circuit breaker arc extinction) by primary Protection not exceeding: Network Category Fault Clearance Times 110 kV 120 millisecond 115 kV 120 millisecond 132 kV 120 millisecond 230 kV 100 millisecond 380 kV 80 millisecond The probability that these times will be exceeded for any given Fault must be less than one (1)%. 2.5.2.7 To safeguard against failure of the primary Protection Systems provided to meet the above Fault clearance time requirements, the Users shall also Chapter 2 - Connection Code The Saudi Arabian Grid Code Updated Version: May 2024 provide backup Protection, which shall have Fault clearance time slower than that specified for the User primary Protection. The TSP shall also provide backup Protection, which shall have Fault clearance times slower than those of the User backup Protection. 2.5.2.8 In case of the failure to trip a User’s circuit breaker provided to interrupt Fault current interchange with the Transmission System, circuit breaker fail Protection shall be provided to trip all necessary electrically adjacent circuit breakers within 300 milliseconds. The design reliability for Protection shall be equal to or greater than 99%. 2.5.2.9 Fault Disconnection Facilities Where no circuit breaker is provided at the User Connection Point, the User must provide to the TSP all necessary facilities and schemes to isolate with discrimination and as necessary the Faults or Grid abnormalities, due to the User Connection, on the Transmission System. In these circumstances, for Faults on the User System, the User Protection should also trip higher voltage TSP circuit breakers. These tripping facilities shall be in accordance with the requirements specified in the relevant Connection Agreement. 2.5.2.10 Loss of Excitation Protection for Synchronous Generating Units The Generator shall provide Protection to detect loss of Generating Unit Excitation and initiate a trip of the associated Generating Unit. 2.5.2.11 Pole Slip Protection for Synchronous Generating Units Where, in the TSP’s reasonable opinion, System requirements dictate, the TSP shall specify in the Connection Agreement and/or Use of System Agreement a requirement for Generators to fit pole slip Protection on their Generating Units. 2.5.2.12 Access to Protection Equipment at Connection Points No Busbar Protection, mesh corner Protection, circuit breaker fail Protection relays, AC or DC wiring (other than Power supplies or DC tripping associated with the User’s Plant and Apparatus) shall be worked upon or altered by, or on behalf of, a User in the absence of a representative of, or written authority from, the TSP. Chapter 2 - Connection Code The Saudi Arabian Grid Code Updated Version: May 2024 2.5.2.13 Automatic Switching Equipment Where automatic re-closing of TSP circuit breakers is required following Faults on the User System, automatic switching Equipment shall be provided in accordance with the requirements of the relevant Connection Agreement. 2.5.2.14 Relay Settings (i) Protection and relay settings shall be coordinated by the TSP and User(s) across the Connection Point in accordance with the Connection Agreement to ensure effective Disconnection of faulty Apparatus. In case of a dispute between any party on such issues, the TSP shall be the final deciding authority. (ii) The TSP may install special Protection Schemes to safeguard against collapse of the System for any foreseeable situation, e.g. during high summer load seasons. In the event of loss of major Transmission line(s) leading to voltage collapse in the Transmission System, the TSP may need to resort to a large scale load shedding to halt damaging voltage collapse which may lead to brownouts and eventual blackouts. The auxiliary load of a NPP shall be considered as high priority critical load.