Large Embedded Generators Register of Completed Projects This document contains a description of the completed projects relating to the connection of Large Embedded Generators to the TasNetworks distribution network. A Large Embedded Generator is considered to be either: a generator that exports into the distribution network through a single connection point at greater than 5 MW; or a generator that exports into the distribution network through a single connection point at less than 5 MW and which has to be registered with AEMO 1. There have been only two Large Generation connections to the TasNetworks distribution network in the last five years. Details of these are given below. 1 The Australian Energy Market Operator
Embedded Generation Projects complete as at 30 January 2015 Generator 1 Technology of generating unit Maximum power generation capacity of the generating system Maximum contribution to fault level Size and rating of the relevant transformer Renewable, hydro gravity, Leroy Somer, LSA 58 65 / 6p / vertical Synchronous generator. 6,078 kw, 7,150 kva @ rated power factor of 0.85. Up to 2,000 amps maximum at the Connection Point. Generator transformer rating 7.5/6 MVA (22/3.3 kv). Single line diagram of the connection arrangement 2
Protection systems and communication systems Voltage control and reactive power capability Location specific facilities required to support the generator connection Protection systems Site disconnection for faults within private HV network; Anti islanding solution installed to ensure that the generating unit only connects to a network that is in a satisfactory operating state; Generator can only be connected to the distribution network with STATCOM in service. Communications Systems SCADA systems have been installed to provide the network service provider with visibility of: Private CB Status relevant to generator connection; Power flows and voltages at the connection site; and Power flows and voltages at the generator connection. Generating unit operates in Voltage Control mode to 1.02 PU. Power factor maintained between 0.95 and 0.98 lagging (absorbing reactive power). STATCOM installation (network side of the main site connection) required to provide voltage support for the distribution network following loss of generator. Anti islanding solution based on microwave and radio communications installed to prevent generator exporting electricity to an islanded portion of the distribution network. Upstream network augmentation completed to accommodate generator capability. Cogeneration control settings applied to voltage regulating controllers. Joint operating procedure developed between Customer and the Network Service Provider to accommodate operational limitations specific to this installation. 3
Generator 2 Technology of generating unit Maximum power generation capacity of the generating system Maximum contribution to fault level Size and rating of the relevant transformer Synchronous generator manufactured by General Electric Company. Natural gas fired turbine manufactured by Siemens. 7,900 kw. Up to 3,000 amps maximum at the Connection Point. Generator connection is via a 22/11kV, 10 MVA step up transformer to the customers high voltage distribution network. TasNetworks Customer Generator s Anti-Islanding Trip Signal HV Feeder HV Connection Site Main CB Generator Connection Site Single line diagram of the connection arrangement Metering HV Connection Point & PCC LV Distribution Board A LV Distribution Board B Generating Unit 4
Protection systems and communication systems Voltage control and reactive power capability Location specific facilities required to support the generator connection Protection systems Anti islanding systems incorporate Rate of change of frequency (ROCOF) and Vector phase shift (VPS) protection relays for the prevention of embedded generating unit islanded operation; Neutral voltage displacement (NVD) protection has been installed for the detection of distribution network earth faults and the prevention of embedded generating unit islanded operation. Communications systems SCADA based truth table solution implemented to ensure generating unit is only connected to a network in a satisfactory operating state. Power factor at the connection point will be maintained between 0.9 lagging to 0.9 leading. Joint operating procedure developed between Customer and the Network Service Provider to accommodate operational limitations specific to this installation. 5