Understanding the J Glover Pocket Reference for Power Systems Work
The J Glover Pocket Reference is a compact compilation of equations, tables, and design constants pulled from the broader power system analysis literature. Most people in the utility and industrial sectors know it by the names of its authors, Glover, Sarma, and Overbye. You will find it useful on the field, at the desk, or when you need quick lookups without dragging out the full textbook. I keep one on my shelf because it saves me from flipping through hundreds of pages when I just need a quick formula for impedance calculations or transformer connections. The book is organized around three core areas: per-unit systems, transmission line parameters, and power flow basics. The per-unit section alone is worth the purchase if you work with transformers or multi-voltage systems regularly. You get the base conversion formulas, the standard impedance bases, and the common pitfalls laid out in one place. The transmission line chapter includes the Carson equations for earth-return impedance, which are rarely memorized by anyone except people who actually use them. The power flow section covers the Gauss-Seidel and Newton-Raphson methods at a high level, enough to understand what your software is doing without drowning in the derivations. I found a real gap in the reference when I was working on a substation grounding study a few years back. The book covers positive and zero sequence networks for transmission lines in decent detail, but it barely mentions how mutual coupling between parallel circuits affects zero-sequence impedance in a double-circuit line arrangement. This came up when I was modeling a 230 kV double-circuit corridor and the protection coordination numbers were off by nearly twelve percent. The workaround was to take the single-circuit zero-sequence impedance from the reference and then apply the mutual coupling factor separately using the Campbell equation. It added about twenty minutes to the setup, but it saved me from going back to the client with incorrect relay settings. If you are dealing with parallel lines, do not assume the reference gives you everything. Go to the source material or a dedicated grounding textbook for the mutual impedance part.
The per-unit system chapter has a nuance that beginners often miss. The book shows you how to convert impedances between bases, but it does not emphasize enough that transformer tap positions change the effective base voltage on the secondary side. I had a situation where a utility provided impedance values for a tap changer at mid-position, but the transformer was actually running at plus five percent tap. Using the reference values directly gave me a voltage drop calculation that was about three percent too low. The fix was straightforward: adjust the base voltage on the secondary side based on the actual tap position before converting any impedances. This is the kind of detail that costs you time in the field if you learn it the hard way.
How to Use It in Practice
The reference is not meant to be read cover to cover. You pull it out for specific lookups. When you are doing a quick load flow check on a radial feeder, go straight to the per-unit conversion tables and the impedance values for common conductor types. The transmission line parameter tables include AC resistance, inductive reactance, and capacitive reactance for standard ACSR and Aluminum Conductor Composite Core conductors up to about 500 kV. These tables are accurate for frequencies between 50 and 60 hertz. If you are working on a traction system or a harmonic study at higher frequencies, the tables will not help you much. You need to calculate skin effect and proximity effect adjustments yourself or use a specialized tool. One thing the book handles well is the symmetrical component transformations for three-phase systems. The matrix formulations are clean, and the worked examples for line-to-ground and line-to-line faults are correct. However, the fault current calculations assume a solid fault with zero impedance. In reality, arcing faults and fault resistance through vegetation or structures can reduce fault currents by twenty to forty percent on distribution circuits. The reference does not guide you through resistance incorporation. I usually add the fault resistance as an additional series impedance in my model after setting up the symmetrical component network from the book. It takes a minute and it makes the results significantly more realistic.
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Limitations You Should Know About
The J Glover Pocket Reference is not a replacement for a full power system analysis text. It does not cover state estimation, optimal power flow, or transient stability. If your work involves any of those areas, you will need additional resources. The book also predates some of the modern computational tools, so the numerical methods section is somewhat terse. It describes the algorithms but does not provide code or worked numerical examples beyond the basic ones. For someone who just needs the theory, this is fine. For someone who needs to implement the methods from scratch, you will find yourself cross-referencing other sources. The coverage of renewable integration is minimal. There is no discussion of inverter-based resource modeling, grid-forming versus grid-following inverters, or the stability issues that come with high penetration of wind and solar. If you are doing modern grid studies, this gap matters. I supplement the reference with papers from IEEE Transactions on Power Systems and the CIGRE technical brochures for anything related to inverter dynamics. You can find the book through standard academic and technical publishers. It is available in paperback and as a digital version from most technical book retailers. The latest edition updates the conductor tables and adds a section on high-temperature low-sag conductors, which is relevant if you work on thermal rating assessments. The reference is priced reasonably for what it contains, and it is small enough to carry in a bag or keep on a desk. I have had mine for about five years and it still holds up for day-to-day field calculations and quick design checks.
