{"id":3664,"date":"2026-04-08T05:39:51","date_gmt":"2026-04-08T05:39:51","guid":{"rendered":"https:\/\/xbrele.com\/?p=3664"},"modified":"2026-04-08T05:39:53","modified_gmt":"2026-04-08T05:39:53","slug":"sfra-transformer-testing-guide","status":"publish","type":"post","link":"https:\/\/xbrele.com\/de\/sfra-transformer-testing-guide\/","title":{"rendered":"SFRA-Transformatorentests 2026: Ergebnisse und Akzeptanzleitfaden"},"content":{"rendered":"<p>Sweep Frequency Response Analysis detects mechanical deformation inside power transformers by measuring how windings respond across thousands of frequencies. When winding geometry shifts\u2014from short-circuit forces, transportation damage, or progressive aging\u2014the frequency response signature changes measurably. This diagnostic technique identifies faults that conventional electrical tests miss: axial displacement, radial buckling, core movement, and connection degradation.<\/p>\n<hr \/>\n<h2>How SFRA Testing Works: Measurement Principles<\/h2>\n<p>SFRA treats transformer windings as complex RLC networks. Each turn contributes distributed inductance. Each insulation layer adds capacitance. The core, clamping structures, and lead arrangements all influence how signals propagate through this electrical network.<\/p>\n<p>During testing, instruments inject a low-voltage sinusoidal signal (typically 1\u201310 V) and sweep from 20 Hz to 2 MHz. At each frequency point, the system measures the output-to-input voltage ratio in decibels, creating a unique &#8220;fingerprint&#8221; trace. Modern instruments achieve resolution of 10 points per decade or finer, with typical amplitude ranges from 0 dB to -80 dB depending on winding configuration.<\/p>\n<p>The physics divides into distinct diagnostic regions:<\/p>\n<ul>\n<li><strong>Low frequency (20 Hz \u2013 2 kHz):<\/strong> Core magnetizing inductance and bulk winding inductance dominate; sensitive to core defects and residual magnetization<\/li>\n<li><strong>Mid frequency (2 kHz \u2013 20 kHz):<\/strong> Interaction between inductance and winding-to-winding capacitance; reveals inter-winding faults<\/li>\n<li><strong>High frequency (20 kHz \u2013 1 MHz):<\/strong> Winding series capacitance and conductor geometry effects; detects localized deformation with resolution down to 1\u20132% winding displacement<\/li>\n<li><strong>Very high frequency (>1 MHz):<\/strong> Test lead and connection artifacts; generally excluded from analysis<\/li>\n<\/ul>\n<p>According to IEC 60076-18 (Power transformers\u2014Measurement of frequency response), test voltage levels should remain below 10 V RMS to avoid influencing the transformer&#8217;s magnetic state. Changes in mechanical geometry as small as 1\u20132 mm in winding position can produce measurable frequency shifts.<\/p>\n<figure class=\"wp-block-image size-large\"><img decoding=\"async\" src=\"https:\/\/xbrele.com\/wp-content\/uploads\/2026\/04\/sfra-transformer-winding-rlc-network-frequency-regions-01.webp\" alt=\"** \" class=\"wp-image-3660\" width=\"1200\" height=\"675\" srcset=\"https:\/\/xbrele.com\/wp-content\/uploads\/2026\/04\/sfra-transformer-winding-rlc-network-frequency-regions-01.webp 1200w, https:\/\/xbrele.com\/wp-content\/uploads\/2026\/04\/sfra-transformer-winding-rlc-network-frequency-regions-01-300x169.webp 300w, https:\/\/xbrele.com\/wp-content\/uploads\/2026\/04\/sfra-transformer-winding-rlc-network-frequency-regions-01-1024x576.webp 1024w, https:\/\/xbrele.com\/wp-content\/uploads\/2026\/04\/sfra-transformer-winding-rlc-network-frequency-regions-01-768x432.webp 768w, https:\/\/xbrele.com\/wp-content\/uploads\/2026\/04\/sfra-transformer-winding-rlc-network-frequency-regions-01-18x10.webp 18w\" sizes=\"(max-width: 1200px) 100vw, 1200px\" \/><figcaption class=\"wp-element-caption\">** <\/figcaption><\/figure>\n<hr \/>\n<h2>When to Perform SFRA Testing: Triggers and Timing<\/h2>\n<p>Field experience across 200+ transformer diagnostics reveals clear patterns for when SFRA delivers maximum value. The technique excels after events that generate mechanical stress\u2014but baseline measurements must exist first.<\/p>\n<h3>Mandatory Testing Points<\/h3>\n<table>\n<thead>\n<tr>\n<th>Scenario<\/th>\n<th>Timing<\/th>\n<th>Purpose<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Factory acceptance<\/td>\n<td>Before shipment<\/td>\n<td>Establish manufacturer baseline<\/td>\n<\/tr>\n<tr>\n<td>Post-transportation<\/td>\n<td>Before oil filling<\/td>\n<td>Detect transit damage<\/td>\n<\/tr>\n<tr>\n<td>Commissioning<\/td>\n<td>Before energization<\/td>\n<td>Confirm installation integrity<\/td>\n<\/tr>\n<tr>\n<td>Post-fault event<\/td>\n<td>Within 48 hours<\/td>\n<td>Assess through-fault damage<\/td>\n<\/tr>\n<tr>\n<td>Periodic assessment<\/td>\n<td>Every 3\u20135 years<\/td>\n<td>Trend mechanical condition<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h3>Event-Driven Triggers<\/h3>\n<p>Through-fault currents generate electromagnetic forces proportional to current squared. An 8 kA fault produces four times the mechanical stress of a 4 kA fault. IEEE C57.149 recommends SFRA assessment after any through-fault event exceeding 70% of rated short-circuit withstand current.<\/p>\n<p>Other triggers warranting immediate testing include Buchholz relay operation, sudden pressure relay activation, unexplained DGA gas increases (particularly acetylene), audible winding noise changes, and seismic events at the installation site.<\/p>\n<p>For <a href=\"https:\/\/xbrele.com\/power-distribution-transformers\/\">power distribution transformers<\/a> entering critical service, baseline SFRA at commissioning provides the reference needed for all future comparisons. Without this baseline, interpretation relies on phase-to-phase comparison\u2014a less sensitive approach.<\/p>\n<figure class=\"wp-block-image size-large\"><img decoding=\"async\" src=\"https:\/\/xbrele.com\/wp-content\/uploads\/2026\/04\/sfra-testing-trigger-decision-flowchart-transformer-02.webp\" alt=\"** \" class=\"wp-image-3661\" width=\"1200\" height=\"675\" srcset=\"https:\/\/xbrele.com\/wp-content\/uploads\/2026\/04\/sfra-testing-trigger-decision-flowchart-transformer-02.webp 1200w, https:\/\/xbrele.com\/wp-content\/uploads\/2026\/04\/sfra-testing-trigger-decision-flowchart-transformer-02-300x169.webp 300w, https:\/\/xbrele.com\/wp-content\/uploads\/2026\/04\/sfra-testing-trigger-decision-flowchart-transformer-02-1024x576.webp 1024w, https:\/\/xbrele.com\/wp-content\/uploads\/2026\/04\/sfra-testing-trigger-decision-flowchart-transformer-02-768x432.webp 768w, https:\/\/xbrele.com\/wp-content\/uploads\/2026\/04\/sfra-testing-trigger-decision-flowchart-transformer-02-18x10.webp 18w\" sizes=\"(max-width: 1200px) 100vw, 1200px\" \/><figcaption class=\"wp-element-caption\">** <\/figcaption><\/figure>\n<blockquote><p><strong>[Expert Insight: Field Deployment Considerations]<\/strong><br \/>\n&#8211; Temperature affects low-frequency response; test at similar ambient conditions as baseline when possible<br \/>\n&#8211; Residual magnetization from recent DC resistance tests can shift low-frequency traces\u2014demagnetize before SFRA if practical<br \/>\n&#8211; Document tap changer position exactly; different positions produce different valid signatures<br \/>\n&#8211; Mining and industrial substations with frequent motor starting experience cumulative through-fault stress\u2014annual SFRA trending proves valuable<\/p><\/blockquote>\n<hr \/>\n<h2>SFRA Test Setup: Configurations and Measurement Protocol<\/h2>\n<p>Three primary measurement configurations provide comprehensive transformer assessment. Each emphasizes different frequency regions and fault sensitivities.<\/p>\n<h3>End-to-End Open Circuit<\/h3>\n<p>\\n<\/p>\n<p>Signal injected at one terminal, measured at opposite terminal of same winding, all other terminals floating. This configuration captures the full winding response and reveals bulk geometry changes. Most sensitive to core-related issues at low frequencies.<\/p>\n<h3>End-to-End Short Circuit<\/h3>\n<p>\\n<\/p>\n<p>Same injection and measurement points, but with secondary windings shorted. The short circuit eliminates core inductance influence, increasing sensitivity to winding series inductance changes. Particularly effective for detecting axial winding displacement.<\/p>\n<h3>Capacitive Interwinding<\/h3>\n<p>\\n<\/p>\n<p>Signal injected on HV winding, measured on LV winding with all terminals floating. This configuration emphasizes inter-winding capacitance and detects changes in the insulation geometry between windings.<\/p>\n<table>\n<thead>\n<tr>\n<th>Configuration<\/th>\n<th>Primary Sensitivity<\/th>\n<th>Frequency Region<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>End-to-end open<\/td>\n<td>Core defects, bulk movement<\/td>\n<td>20 Hz \u2013 20 kHz<\/td>\n<\/tr>\n<tr>\n<td>End-to-end short<\/td>\n<td>Winding deformation<\/td>\n<td>2 kHz \u2013 200 kHz<\/td>\n<\/tr>\n<tr>\n<td>Capacitive interwinding<\/td>\n<td>Insulation geometry<\/td>\n<td>10 kHz \u2013 1 MHz<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h3>Critical Setup Requirements<\/h3>\n<p>Connection quality dominates high-frequency accuracy. Use dedicated SFRA test leads\u2014standard multimeter leads introduce unacceptable impedance at frequencies above 100 kHz. Clean bushing terminals thoroughly before connecting. Maintain consistent lead routing between tests; lead movement shifts high-frequency response.<\/p>\n<p>Ground configuration matters. Connect the instrument ground to the transformer tank at a single point. Avoid ground loops through multiple connections.<\/p>\n<figure class=\"wp-block-image size-large\"><img decoding=\"async\" src=\"https:\/\/xbrele.com\/wp-content\/uploads\/2026\/04\/sfra-test-configurations-open-short-interwinding-03.webp\" alt=\"** \" class=\"wp-image-3662\" width=\"1200\" height=\"675\" srcset=\"https:\/\/xbrele.com\/wp-content\/uploads\/2026\/04\/sfra-test-configurations-open-short-interwinding-03.webp 1200w, https:\/\/xbrele.com\/wp-content\/uploads\/2026\/04\/sfra-test-configurations-open-short-interwinding-03-300x169.webp 300w, https:\/\/xbrele.com\/wp-content\/uploads\/2026\/04\/sfra-test-configurations-open-short-interwinding-03-1024x576.webp 1024w, https:\/\/xbrele.com\/wp-content\/uploads\/2026\/04\/sfra-test-configurations-open-short-interwinding-03-768x432.webp 768w, https:\/\/xbrele.com\/wp-content\/uploads\/2026\/04\/sfra-test-configurations-open-short-interwinding-03-18x10.webp 18w\" sizes=\"(max-width: 1200px) 100vw, 1200px\" \/><figcaption class=\"wp-element-caption\">** <\/figcaption><\/figure>\n<hr \/>\n<h2>How to Read SFRA Results: Frequency Band Interpretation<\/h2>\n<p>Successful SFRA interpretation requires systematic analysis across frequency bands, correlating deviations with probable physical causes. Raw traces mean nothing without comparison\u2014either against historical baselines, phase-to-phase references, or sister unit data.<\/p>\n<h3>Low Frequency Region (20 Hz \u2013 2 kHz)<\/h3>\n<p>\\n<\/p>\n<p>Core magnetizing inductance dominates. Look for:<br \/>\n&#8211; First resonance frequency shift indicating core clamping issues<br \/>\n&#8211; Magnitude changes suggesting shorted core laminations<br \/>\n&#8211; Response shape differences from residual magnetization<\/p>\n<h3>Mid Frequency Region (2 kHz \u2013 20 kHz)<\/h3>\n<p>\\n<\/p>\n<p>Main winding inductance and inter-winding capacitance interact. This region reveals:<br \/>\n&#8211; Bulk winding displacement (axial or radial)<br \/>\n&#8211; Inter-winding short circuits<br \/>\n&#8211; Major lead connection changes<\/p>\n<h3>High Frequency Region (20 kHz \u2013 1 MHz)<\/h3>\n<p>\\n<\/p>\n<p>Localized winding geometry effects appear here. Detection includes:<br \/>\n&#8211; Turn-to-turn faults<br \/>\n&#8211; Localized winding deformation<br \/>\n&#8211; Tap winding problems<\/p>\n<h3>Comparison Methods<\/h3>\n<p><em>Time-based comparison<\/em> offers highest sensitivity. Comparing current traces against historical baselines from the same unit detects changes as small as 1\u20132% winding displacement. This requires reliable historical data.<\/p>\n<p><em>Phase-to-phase comparison<\/em> works when baselines don&#8217;t exist. On three-phase transformers, comparing A-phase to B-phase to C-phase reveals asymmetric damage. Outer phases may show slight systematic differences from center phase on five-limb core designs\u2014this is normal.<\/p>\n<p><em>Sister unit comparison<\/em> provides reference when neither baseline nor phase symmetry applies. Manufacturing tolerances mean sister units may differ by 2\u20133 dB at certain frequencies even when both are healthy.<\/p>\n<p>Integration with <a href=\"https:\/\/xbrele.com\/vacuum-circuit-breaker\/\">vacuum circuit breaker<\/a> protection systems matters for post-fault assessment. Breaker operation records document fault current magnitude and clearing time\u2014data essential for evaluating whether observed SFRA deviations correlate with mechanical stress levels.<\/p>\n<hr \/>\n<h2>SFRA Acceptance Criteria: Decision Thresholds<\/h2>\n<p>Interpreting SFRA results demands balancing statistical metrics with engineering judgment. No single threshold guarantees correct decisions\u2014context determines appropriate action.<\/p>\n<h3>Correlation Coefficient Analysis<\/h3>\n<p>IEC 60076-18 recommends correlation coefficient calculation between reference and measured traces. Field experience suggests these practical thresholds:<\/p>\n<table>\n<thead>\n<tr>\n<th>Frequency Region<\/th>\n<th>Acceptable<\/th>\n<th>Investigate<\/th>\n<th>Reject<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>20 Hz \u2013 2 kHz<\/td>\n<td>CC &gt; 0.99<\/td>\n<td>0.97\u20130.99<\/td>\n<td>&lt; 0.97<\/td>\n<\/tr>\n<tr>\n<td>2 kHz \u2013 500 kHz<\/td>\n<td>CC &gt; 0.95<\/td>\n<td>0.90\u20130.95<\/td>\n<td>&lt; 0.90<\/td>\n<\/tr>\n<tr>\n<td>500 kHz \u2013 2 MHz<\/td>\n<td>CC &gt; 0.90<\/td>\n<td>0.85\u20130.90<\/td>\n<td>&lt; 0.85<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>[VERIFY STANDARD: Specific correlation coefficient thresholds vary between IEC 60076-18 and IEEE C57.149; verify applicable standard for contractual acceptance testing]<\/p>\n<h3>Deviation Magnitude Assessment<\/h3>\n<p>The absolute deviation method measures decibel differences at corresponding frequency points:<br \/>\n&#8211; Below 3 dB: Generally within measurement repeatability<br \/>\n&#8211; 3\u20136 dB: Investigate further; may indicate developing issues<br \/>\n&#8211; Above 6 dB: Strongly suggests mechanical displacement requiring intervention<\/p>\n<h3>Contextual Factors<\/h3>\n<p>Transformer criticality influences acceptable risk. A 5 dB deviation on a 100 MVA transmission autotransformer justifies immediate investigation. Similar deviation on a 2 MVA distribution unit may permit continued monitoring with shortened assessment intervals.<\/p>\n<p>Comparison quality affects threshold stringency. Time-based comparison against reliable factory baseline permits tighter limits than phase-to-phase comparison on units with unknown history.<\/p>\n<p>For <a href=\"https:\/\/xbrele.com\/oil-immersed-transformer\/\">oil-immersed transformers<\/a> showing borderline SFRA results, correlate findings with dissolved gas analysis. Mechanical faults often generate characteristic gases\u2014acetylene from arcing, ethylene from hot spots. Consistent findings across multiple diagnostic methods strengthen confidence in conclusions.<\/p>\n<blockquote><p><strong>[Expert Insight: Acceptance Decision Realities]<\/strong><br \/>\n&#8211; Correlation coefficients screen for problems but don&#8217;t diagnose them\u2014low CC identifies &#8220;something changed,&#8221; not &#8220;what changed&#8221;<br \/>\n&#8211; High-frequency deviations (&gt;500 kHz) often reflect connection differences rather than winding problems; verify lead routing before concluding fault<br \/>\n&#8211; Phase-to-phase comparison on delta windings requires careful terminal identification; misidentified phases produce false alarms<br \/>\n&#8211; When historical and sister unit comparisons disagree, weight historical data higher\u2014it reflects this specific unit&#8217;s characteristics<\/p><\/blockquote>\n<figure class=\"wp-block-image size-large\"><img decoding=\"async\" src=\"https:\/\/xbrele.com\/wp-content\/uploads\/2026\/04\/sfra-acceptance-criteria-correlation-threshold-flowchart-04.webp\" alt=\"** \" class=\"wp-image-3663\" width=\"1200\" height=\"675\" srcset=\"https:\/\/xbrele.com\/wp-content\/uploads\/2026\/04\/sfra-acceptance-criteria-correlation-threshold-flowchart-04.webp 1200w, https:\/\/xbrele.com\/wp-content\/uploads\/2026\/04\/sfra-acceptance-criteria-correlation-threshold-flowchart-04-300x169.webp 300w, https:\/\/xbrele.com\/wp-content\/uploads\/2026\/04\/sfra-acceptance-criteria-correlation-threshold-flowchart-04-1024x576.webp 1024w, https:\/\/xbrele.com\/wp-content\/uploads\/2026\/04\/sfra-acceptance-criteria-correlation-threshold-flowchart-04-768x432.webp 768w, https:\/\/xbrele.com\/wp-content\/uploads\/2026\/04\/sfra-acceptance-criteria-correlation-threshold-flowchart-04-18x10.webp 18w\" sizes=\"(max-width: 1200px) 100vw, 1200px\" \/><figcaption class=\"wp-element-caption\">** <\/figcaption><\/figure>\n<hr \/>\n<h2>Integrating SFRA with Complementary Diagnostics<\/h2>\n<p>SFRA excels at detecting mechanical changes but provides incomplete pictures alone. Comprehensive transformer assessment combines multiple techniques, each revealing different failure modes.<\/p>\n<h3>Dissolved Gas Analysis (DGA)<\/h3>\n<p>\\n<\/p>\n<p>Mechanical faults generate gases. Acetylene indicates arcing. Ethylene suggests localized overheating. When SFRA shows winding displacement and DGA shows rising acetylene, confidence in mechanical damage increases substantially.<\/p>\n<h3>Winding Resistance<\/h3>\n<p>\\n<\/p>\n<p>Shorted turns detected by SFRA should produce corresponding resistance anomalies. If SFRA indicates turn-to-turn faults but winding resistance remains normal, investigate measurement quality before concluding transformer health.<\/p>\n<h3>Short-Circuit Impedance<\/h3>\n<p>\\n<\/p>\n<p>Winding movement changes leakage reactance. Trend short-circuit impedance alongside SFRA\u2014both should show correlated changes for genuine mechanical displacement.<\/p>\n<h3>Power Factor \/ Dissipation Factor<\/h3>\n<p>\\n<\/p>\n<p>Insulation condition affects capacitive response. Significant power factor changes may correlate with SFRA high-frequency deviations if insulation degradation alters geometry.<\/p>\n<p>For <a href=\"https:\/\/xbrele.com\/dry-type-transformer\/\">dry-type transformers<\/a>, visual inspection complements SFRA effectively. Without oil obscuring the active part, winding deformation may be directly visible through ventilation openings\u2014confirmation impossible on oil-filled units.<\/p>\n<hr \/>\n<h2>XBRELE Transformer Diagnostic and Engineering Support<\/h2>\n<p>SFRA interpretation benefits from manufacturer-specific knowledge. Design details\u2014winding geometry, insulation systems, clamping arrangements\u2014influence expected frequency response characteristics and acceptable deviation ranges.<\/p>\n<p>XBRELE&#8217;s transformer engineering team provides:<\/p>\n<ul>\n<li>Design-specific baseline data for reference comparison<\/li>\n<li>Engineering assessment of SFRA deviation significance<\/li>\n<li>Repair feasibility evaluation for units showing mechanical damage<\/li>\n<li>Replacement recommendations when repair costs exceed economic thresholds<\/li>\n<\/ul>\n<p>For diagnostic consultation on <a href=\"https:\/\/xbrele.com\/distribution-transformer-manufacturer\/\">distribution transformer<\/a> SFRA interpretation, contact XBRELE&#8217;s technical support team. Access to original design documentation enables confident assessment of whether observed deviations indicate actionable problems or acceptable manufacturing variation.<\/p>\n<hr \/>\n<h2>Frequently Asked Questions<\/h2>\n<h3>How long does SFRA testing take on a typical distribution transformer?<\/h3>\n<p>\\n<\/p>\n<p>Complete SFRA assessment including all three configurations requires 2\u20134 hours for a three-phase distribution transformer, with additional time needed for connection setup, documentation, and preliminary on-site analysis.<\/p>\n<h3>Can SFRA detect partial discharge activity?<\/h3>\n<p>\\n<\/p>\n<p>SFRA does not detect partial discharge directly; it measures mechanical geometry through frequency response signatures. Partial discharge assessment requires dedicated PD measurement equipment operating on different principles.<\/p>\n<h3>What causes resonance frequency shifts in SFRA traces?<\/h3>\n<p>\\n<\/p>\n<p>Resonance frequency shifts result from changes in effective inductance or capacitance\u2014winding displacement alters both parameters. Upward frequency shifts typically indicate reduced inductance (compressed windings), while downward shifts suggest increased inductance (separated windings or loosened clamping).<\/p>\n<h3>Is SFRA testing safe for energized transformers?<\/h3>\n<p>\\n<\/p>\n<p>SFRA requires the transformer to be de-energized and isolated. The test injects signals into windings that would be overwhelmed by power frequency voltages, and personnel safety requires lockout-tagout procedures before connection.<\/p>\n<h3>How do ambient temperature variations affect SFRA measurements?<\/h3>\n<p>\\n<\/p>\n<p>Temperature primarily influences low-frequency response through core permeability and oil viscosity effects. For reliable comparison, test at ambient conditions within \u00b110\u00b0C of baseline measurements, or apply temperature correction factors if wider variations exist.<\/p>\n<h3>Can transportation damage be detected immediately after delivery?<\/h3>\n<p>\\n<\/p>\n<p>Yes, post-transportation SFRA comparison against factory baseline effectively reveals shipping damage. Best practice calls for SFRA at the factory before shipment and again at site before oil filling\u2014comparing these traces identifies transit-induced mechanical displacement.<\/p>\n<h3>What training is required to perform SFRA testing?<\/h3>\n<p>\\n<\/p>\n<p>Competent SFRA testing requires understanding of transformer construction, measurement equipment operation, and connection protocols. Interpretation demands deeper expertise\u2014most utilities either develop specialist teams or engage manufacturer support for result analysis.<\/p>\n<hr \/>\n<p><em>Technical content reflects field diagnostic practices for medium-voltage and high-voltage power transformers. Specific acceptance thresholds should align with asset owner policies, applicable standards, and transformer criticality assessments.<\/em><\/p>\n<hr \/>\n","protected":false},"excerpt":{"rendered":"<p>Sweep Frequency Response Analysis detects mechanical deformation inside power transformers by measuring how windings respond across thousands of frequencies. When winding geometry shifts\u2014from short-circuit forces, transportation damage, or progressive aging\u2014the frequency response signature changes measurably. This diagnostic technique identifies faults that conventional electrical tests miss: axial displacement, radial buckling, core movement, and connection degradation. How [&hellip;]<\/p>\n","protected":false},"author":3,"featured_media":3665,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_gspb_post_css":"","footnotes":""},"categories":[26],"tags":[],"class_list":["post-3664","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-power-distribution-transformer-knowledge"],"blocksy_meta":[],"_links":{"self":[{"href":"https:\/\/xbrele.com\/de\/wp-json\/wp\/v2\/posts\/3664","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/xbrele.com\/de\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/xbrele.com\/de\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/xbrele.com\/de\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/xbrele.com\/de\/wp-json\/wp\/v2\/comments?post=3664"}],"version-history":[{"count":3,"href":"https:\/\/xbrele.com\/de\/wp-json\/wp\/v2\/posts\/3664\/revisions"}],"predecessor-version":[{"id":3740,"href":"https:\/\/xbrele.com\/de\/wp-json\/wp\/v2\/posts\/3664\/revisions\/3740"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/xbrele.com\/de\/wp-json\/wp\/v2\/media\/3665"}],"wp:attachment":[{"href":"https:\/\/xbrele.com\/de\/wp-json\/wp\/v2\/media?parent=3664"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/xbrele.com\/de\/wp-json\/wp\/v2\/categories?post=3664"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/xbrele.com\/de\/wp-json\/wp\/v2\/tags?post=3664"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}