Inverter-Based Resource Interconnection - Commissioning Test

What it is

The inverter-based resource interconnection commissioning test is the interconnection record for an inverter-based resource other than a wind plant: photovoltaic, battery storage, hybrids of the two, and inverter-coupled fuel cells and microturbines. An interconnection class selector picks one branch - distribution-connected under IEEE 1547 or transmission-connected under IEEE 2800 - and exactly one applies; the fields of the other branch are recorded and never graded. The form records the design evaluation, the applied settings, the field commissioning tests and power quality, and grades each against the interconnecting authority's value or the clause value: every applied setting is read back as an exact match to what the authority specified, trip tests are graded on the applied clearing time, and capability, control mode, islanding and power quality results are graded against the limits of the applicable standard. On the distribution branch a verification class (point-of-connection unit, composite, or point-of-common-coupling system) selects which IEEE 1547.1-2020 commissioning-test set applies. Rotating machines and the plant's own equipment tests are out of scope, and wind turbine plants are recorded on their own form.

Why it is performed

Before an inverter-based resource enters service, the interconnecting authority must know that the unit's protection settings, control modes and power quality meet the requirements of its system and will not degrade voltage, frequency response or protection selectivity for the customers around it. The authority specifies the settings for the site - trip magnitudes and clearing times, enter-service windows, control modes and their parameters - in a setting specification whose document and revision the form records; if the commissioning test then reads a different value back from the controller, the unit has not yet met the condition for service. Verifying the match between every applied setting and the authority's specification, and confirming that the unit trips, ceases to energize, synchronizes, delivers reactive capability and holds power quality as the standard requires, prevents a unit from being left in service with protection or control behavior the authority never agreed to. The record also carries the plant configuration at test time, which the later plant validation uses.

When it is performed

Acceptance: performed in the field after the resource and its interconnection are installed, once the design evaluation is complete and the authority's setting specification is in hand, and before the unit is placed in service; on the transmission branch the prerequisites are that the design and as-built evaluations passed, the test plan was coordinated with the transmission system owner or operator and the written procedure was approved, and a reduced scope is only what was explicitly agreed with that owner or operator. The power quality rows need a Class A analyzer survey of at least seven days, so the record spans the survey; a shorter survey is recorded, not graded. Irradiance, state of charge and the available power at each test are part of the record because the later validation of the plant's dynamic performance uses its configuration at test time, and a run with fewer than about 90 percent of units online is valid but must be stated. This is a commissioning record rather than a periodic maintenance test; it is repeated when the authority requires it after a change to the equipment, the settings or the interconnection requirements.

How it is typically performed

The record opens with identification, the interconnecting authority and its setting specification (document and revision), the design evaluation report, the interconnection class and, on the distribution branch, the verification class, which sets the commissioning-test number of each section. A visual and mechanical inspection covers the installation evaluation items; an unsatisfactory item raises a repair issue. The test source and instruments are recorded, with the measurement system uncertainty held to half the minimum accuracy IEEE 1547-2018 sets, the recorder time resolution, and whether a Class A analyzer was used, which harmonic and flicker grades require; signal injection and actual adjustment are both allowed methods. On the distribution branch the technician then records the evaluation steps of the class, each trip function's specified, default and applied magnitude and clearing time as read back from the controller, the on-off and enter-service demonstrations (enter service inside the window with permit service enabled, the intentional delay, never energizing a de-energized system, cease to energize on an open phase), synchronization differences at closure and the paralleling step, enter-service and control settings with range flags, reactive capability at the test active power and each required control mode, the voltage and frequency trip tests with the trip time recorded as a clearing time at a magnitude beyond the setting, power quality from the survey, interoperability reads and writes on composite classes, the islanding test and any storage rows. On the transmission branch it records the commissioning prerequisites and scope agreement, the ride-through conformity from the type test and design evaluation (never field tested), enter-service and return-to-service tests, protection settings as found and as left with unit trip tests, plant-wide protection checks, control mode, reactive, voltage and power factor control steps, primary and fast frequency response steps, power quality at the reference point of applicability and the measurement data equipment. The report items name who performed and supervised the tests, the secured PDF and CSV with checksum and the applied-settings file.

What gets recorded

Identification and nameplate, including the twenty items of the IEEE 1547 information list, plant ratings, units in service and storage; the authority, its setting specification and the design evaluation report; the interconnection class, the specified and nameplate categories and, in distribution, the verification class. Test source and instruments with uncertainty, time resolution and the Class A selection. Distribution branch: evaluation steps; each trip function's specified, default and applied magnitude and clearing time with read-back match and range flag; on-off, enter-service and shutdown demonstrations with open-phase times; synchronization differences and the paralleling step; enter-service and control settings; reactive injection and absorption and each control mode; trip test method, time basis, magnitude and trip time per function; dc injection, rapid voltage change, flicker, harmonic current by band and total distortion with survey duration and event type; interoperability; islanding cessation time and reclosing; storage rows. Transmission branch: prerequisites and scope; ride-through conformity; enter-service settings as found and as left with step and rate; protection settings as found and as left with measured level and time; plant-wide checks; control mode, reactive, voltage and power factor test values; frequency response settings and per-step times, damping and direction; power quality at the reference point with baseline and operator allocation; recording equipment. Report items, ambient, irradiance, state of charge, comments and deficiencies.

How results are evaluated

The verdict is the sum of the branch that applies. On the distribution branch, every applied trip setting must match the authority's specified value exactly (the IEEE 1547-2018 default stands where the authority specified nothing), a nameplate abnormal category below the specified category fails, and a setting past the limiting edge of its allowable range fails. The on-off items must be demonstrated, the unit must cease to energize within 2.0 s of an open phase, synchronization must stay within the IEEE 1547-2018 row for the aggregate rating and the paralleling step limit, reactive capability must be at or above the scaled table value, each required control mode and volt-watt limiting must be demonstrated, and each trip test must trip within the applied clearing time at a magnitude beyond the setting and not before the ride-through minimum; a wrong-side magnitude or a relay output time leaves the row ungraded or indeterminate rather than failed. Power quality must be within the IEEE 1547-2018 limits for dc injection, rapid voltage change, flicker and harmonic current, never IEEE 519, from a Class A survey of at least seven days. Required information items must be read and written, and the plant must cease to energize within 2 s of island formation or the agreed value up to 5 s. On the transmission branch, enter-service and primary frequency response settings must match the transmission system operator's values exactly and protection settings must match the design evaluation exactly; the enter-service step and average rate stay within the ICR limits; permit service, return to service, unit trip elements and the measured trip time within the applied setting are graded; voltage control needs a reaction time under 200 ms and a damped response, reactive and power factor control settle within the IEEE 2800-2022 bands, each frequency response step is graded on its times, damping and direction, and power quality at the reference point is graded at the weekly 95th percentile. Range flags on enter-service, control and frequency response settings, an unsatisfactory installation item and storage rows raise issues only. A required evaluation step recorded unsatisfactory fails, and every row the record calls for needs a result or the record reads indeterminate with an issue naming the group. The limit values are in the standards and are not reproduced on this page.